Problem library

All problems

A searchable reference of every problem I have solved, with categories and complexity at a glance.

944 / 944 problems

Problem	Category	Time	Solved
Lowest common ancestor of a binary tree IV tree	tree	O(n)	Aug 7, 2023
Split strings by separator array-and-hashmap	array and hashmap	O(n)	Jul 24, 2023
Number of increasing paths in a grid dynamic-programming graph	dynamic programming graph	O(m*n)	Jun 17, 2023
Missing ranges array-and-hashmap	array and hashmap	O(n)	Jun 14, 2023
Check if all characters have equal number of occurrences array-and-hashmap	array and hashmap	O(n)	Jun 13, 2023
Summary ranges array-and-hashmap	array and hashmap	O(n)	Jun 11, 2023
Maximum value at a given index in a bounded array binary-search	binary search	O(log(n))	Jun 9, 2023
Check if a number is majority element in a sorted array binary-search	binary search	O(n)	Jun 7, 2023
Count negative numbers in a sorted matrix array-and-hashmap	array and hashmap	O(n)	Jun 7, 2023
Can make arithmetic progression from sequence math-and-geometry array-and-hashmap	math and geometry array and hashmap	O(nlog(n))	Jun 5, 2023
Check if it is a straight line math-and-geometry	math and geometry	O(n)	Jun 4, 2023
Time needed to inform all employees graph	graph	O(n)	Jun 2, 2023
Shortest path in binary matrix graph	graph	O(n)	Jun 1, 2023
Number of substrings containing all three characters sliding-window	sliding window	O(n)	May 28, 2023
Vowels of all substrings dynamic-programming	dynamic programming	O(n)	May 28, 2023
Stone game II dynamic-programming	dynamic programming	O(n^2)	May 27, 2023
Stone game III dynamic-programming	dynamic programming	O(n)	May 27, 2023
Univalued binary tree tree	tree	O(n)	May 27, 2023
Count vowel strings in ranges array-and-hashmap	array and hashmap	O(n)	May 24, 2023
Left and right sum differences array-and-hashmap	array and hashmap	O(n)	May 24, 2023
Maximum subsequence score heap	heap	O(nlog(n))	May 23, 2023
Sum in a matrix math-and-geometry	math and geometry	O(nmlog(m))	May 23, 2023
Find three consecutive integers that sum to a given number math-and-geometry	math and geometry	O(1)	May 22, 2023
Split a circular linked list linked-list	linked list	O(n)	May 22, 2023
Kth largest sum in a binary tree heap tree	heap tree	O(nlog(k))	May 21, 2023
K-th smallest prime fraction heap	heap	O(klog(n))	May 20, 2023
Maximum profit from trading stocks dynamic-programming	dynamic programming	O(n)	May 20, 2023
Check if word equals summation of two words array-and-hashmap	array and hashmap	O(n)	May 19, 2023
The kth factor of n math-and-geometry	math and geometry	O(n)	May 19, 2023
Number of adjacent elements with the same color array-and-hashmap	array and hashmap	O(n)	May 18, 2023
Diameter of N-ary tree tree	tree	O(n)	May 17, 2023
Number of good leaf nodes pairs tree	tree	O(n^2)	May 17, 2023
Remove sub folders from the filesystem trie	trie	O(n * m)	May 15, 2023
Consecutive characters array-and-hashmap	array and hashmap	O(n)	May 14, 2023
Count triplets that can form two arrays of equal xor bit-manipulation	bit manipulation	O(n^2)	May 13, 2023
Make array zero by subtracting equal amounts heap math-and-geometry	heap math and geometry	O(nlogn)	May 13, 2023
Maximum product of two elements in an array heap	heap	O(n)	May 13, 2023
Android unlock patterns backtracking	backtracking	O(n!)	May 12, 2023
Count ways to build good strings dynamic-programming	dynamic programming	O(n)	May 12, 2023
Find permutation array-and-hashmap	array and hashmap	O(n)	May 12, 2023
Letter tile possibilities backtracking	backtracking	O(n!)	May 12, 2023
Maximum length of subarray with positive product dynamic-programming	dynamic programming	O(n)	May 11, 2023
Solving questions with brainpower dynamic-programming	dynamic programming	O(n)	May 11, 2023
Equal tree partition tree	tree	O(n)	May 10, 2023
Largest unique number array-and-hashmap	array and hashmap	O(n)	May 10, 2023
Uncrossed lines dynamic-programming	dynamic programming	O(m*n)	May 10, 2023
Increasing order search tree tree	tree	O(n)	May 9, 2023
Prime in diagonal array-and-hashmap	array and hashmap	O(n)	May 8, 2023
Valid boomerang math-and-geometry	math and geometry	O(1)	May 8, 2023
Matrix diagonal sum array-and-hashmap	array and hashmap	O(n)	May 7, 2023
Sort array by increasing frequency array-and-hashmap	array and hashmap	O(nlog(n))	May 7, 2023
Concatenation of array array-and-hashmap	array and hashmap	O(n)	May 6, 2023
Find score of an array after marking all elements heap	heap	O(nlog(n))	May 6, 2023
Find the longest valid obstacle course at each position binary-search	binary search	O(nlogn)	May 6, 2023
Maximum number of vowels in a substring of given length array-and-hashmap	array and hashmap	O(n)	May 5, 2023
Substrings that begin and end with the same letter array-and-hashmap math-and-geometry	array and hashmap math and geometry	O(n)	May 5, 2023
Index pairs of a string array-and-hashmap	array and hashmap	O(n^2)	May 4, 2023
Maximum sum with exactly k elements array-and-hashmap	array and hashmap	O(k)	May 4, 2023
Greatest common divisor of strings math-and-geometry	math and geometry	O(n)	Feb 1, 2023
Sentence similarity array-and-hashmap graph	array and hashmap graph	O(n)	Feb 1, 2023
Best team with no conflicts dynamic-programming	dynamic programming	O(n^2)	Jan 31, 2023
Game of nim bit-manipulation	bit manipulation	O(n)	Jan 29, 2023
LFU cache linked-list design	linked list design	O(1)	Jan 29, 2023
Data stream as disjoint intervals intervals	intervals	O(n)	Jan 28, 2023
Concatenated words trie	trie	O(n^2)	Jan 27, 2023
Find closest node to given two nodes graph	graph	O(n)	Jan 25, 2023
Find minimum time to finish all jobs II greedy	greedy	O(nlog(n))	Jan 24, 2023
Queue reconstruction by height greedy	greedy	O(nlog(n))	Jan 23, 2023
Confusing number II backtracking	backtracking	O(5^log(n))	Jan 22, 2023
Candy array-and-hashmap	array and hashmap	O(n)	Jan 21, 2023
Subarray sums divisible by k array-and-hashmap	array and hashmap	O(n)	Jan 19, 2023
Count the number of good subarray sliding-window	sliding window	O(n)	Jan 18, 2023
Find the celebrity two-pointers	two pointers	O(n)	Jan 17, 2023
Flip string to monotone increasing array-and-hashmap	array and hashmap	O(n)	Jan 17, 2023
Minimum moves to reach target score greedy	greedy	O(log(n))	Jan 16, 2023
Percentage of letter in string array-and-hashmap	array and hashmap	O(n)	Jan 16, 2023
Difference between element sum and digit sum of an array array-and-hashmap	array and hashmap	O(n)	Jan 15, 2023
Find the index of the large integer binary-search	binary search	O(log(n))	Jan 15, 2023
Number of good paths tree	tree	O(nlog(n))	Jan 15, 2023
Lexicographically smallest equivalent string graph	graph	O(n)	Jan 14, 2023
Longest path with different adjacent characters tree	tree	O(n)	Jan 13, 2023
Number of good binary strings dynamic-programming	dynamic programming	O(n)	Jan 13, 2023
Number of nodes in the sub tree with the same label tree	tree	O(n)	Jan 12, 2023
Maximum binary string after change greedy	greedy	O(n)	Jan 11, 2023
Maximum number of points with cost dynamic-programming	dynamic programming	O(mn)	Jan 11, 2023
Minimum time to collect all apples in a tree tree graph	tree graph	O(n)	Jan 11, 2023
Find good days to rob the bank array-and-hashmap	array and hashmap	O(n)	Jan 10, 2023
Shuffle the array array-and-hashmap	array and hashmap	O(n)	Jan 10, 2023
Confusing number array-and-hashmap	array and hashmap	O(log(n))	Jan 9, 2023
Find and replace in string array-and-hashmap	array and hashmap	O(n)	Jan 9, 2023
Maximal score after applying k operations heap	heap	O(klog(n))	Jan 9, 2023
Find xor beauty of array bit-manipulation	bit manipulation	O(n)	Jan 8, 2023
Max points on a line math-and-geometry	math and geometry	O(n^2)	Jan 8, 2023
Minimum health to beat game greedy	greedy	O(n)	Jan 8, 2023
Assign cookies greedy	greedy	O(nlog(n))	Jan 7, 2023
Max increase to keep city skyline greedy	greedy	O(n^2)	Jan 6, 2023
Maximum ice cream bars greedy heap	greedy heap	O(nlog(n))	Jan 6, 2023
Minimum operations to make the array alternating greedy array-and-hashmap	greedy array and hashmap	O(n)	Jan 6, 2023
Most profit assigning work greedy two-pointers	greedy two pointers	O(nlog(n))	Jan 6, 2023
Number of segments in a string array-and-hashmap	array and hashmap	O(n)	Jan 5, 2023
Steps to make array non decreasing stack dynamic-programming	stack dynamic programming	O(n)	Jan 5, 2023
Check if number is a sum of powers of three math-and-geometry	math and geometry	O(log(n))	Jan 4, 2023
Check if there is a valid path in a grid graph	graph	O(mn)	Jan 4, 2023
Convert to base -2 math-and-geometry	math and geometry	O(log(n))	Jan 4, 2023
Delete columns to make sorted array-and-hashmap	array and hashmap	O(nm)	Jan 3, 2023
Finding the number of visible mountains stack	stack	O(nlog(n))	Jan 3, 2023
Car pooling array-and-hashmap	array and hashmap	O(nlogn)	Jan 2, 2023
Divide intervals into minimum number of groups heap intervals	heap intervals	O(nlogn)	Jan 2, 2023
K highest ranked items within a price range heap graph	heap graph	O(mnlog(mn))	Jan 2, 2023
Count the digits that divide a number math-and-geometry	math and geometry	O(n)	Jan 1, 2023
Count the number of k big indices binary-search	binary search	O(nlog(n))	Jan 1, 2023
Distinct prime factors of product of array math-and-geometry	math and geometry	O(nlog(n))	Jan 1, 2023
Sum of all odd length subarrays array-and-hashmap	array and hashmap	O(n^3)	Jan 1, 2023
Two sum bsts tree	tree	O(n)	Jan 1, 2023
Create binary tree from descriptions tree	tree	O(n)	Dec 31, 2022
Sum of all subset xor totals backtracking	backtracking	O(n*2^n)	Dec 31, 2022
Unique paths III backtracking	backtracking	O(n^2)	Dec 31, 2022
3sum smaller array-and-hashmap	array and hashmap	O(n^2)	Dec 30, 2022
adding-spaces-to-a-string array-and-hashmap	array and hashmap	O(n)	Dec 30, 2022
Remove letter to equalize frequency array-and-hashmap	array and hashmap	O(n)	Dec 30, 2022
Leftmost column with at least a one binary-search	binary search	O(mlog(n))	Dec 29, 2022
Count number of ways to place houses math-and-geometry	math and geometry	O(n)	Dec 28, 2022
Design a leaderboard array-and-hashmap design	array and hashmap design	O(1)	Dec 28, 2022
Maximum tastiness of candy basket binary-search	binary search	O(nlog(n))	Dec 28, 2022
Minimum increment to make array unique greedy	greedy	O(nlog(n))	Dec 28, 2022
Minimum path cost in a grid dynamic-programming	dynamic programming	O(nm)	Dec 28, 2022
Minimum penalty for a shop array-and-hashmap greedy	array and hashmap greedy	O(n)	Dec 28, 2022
Minimum remove to make valid parentheses stack	stack	O(n)	Dec 28, 2022
First day where you have been in all the rooms dynamic-programming	dynamic programming	O(n)	Dec 27, 2022
Maximum bags with full capacity of rocks greedy	greedy	O(nlog(n))	Dec 27, 2022
Next palindrome using same digits math-and-geometry	math and geometry	O(n)	Dec 27, 2022
Perfect number math-and-geometry	math and geometry	O(sqrt(n))	Dec 27, 2022
Prefix and suffix search array-and-hashmap design	array and hashmap design	O(n)	Dec 27, 2022
Synonymous sentences graph	graph	O(n^2)	Dec 27, 2022
XOR operation in an array bit-manipulation	bit manipulation	O(n)	Dec 27, 2022
Bitwise or of all subsequence sums bit-manipulation	bit manipulation	O(n)	Dec 26, 2022
Out of boundary paths dynamic-programming	dynamic programming	O(mn)	Dec 26, 2022
Shortest unsorted continuous subarray greedy	greedy	O(nlog(n))	Dec 26, 2022
Count anagrams math-and-geometry	math and geometry	O(n)	Dec 25, 2022
Longest subsequence with limited sum array-and-hashmap	array and hashmap	O(nlog(n))	Dec 25, 2022
Minimum number of moves to make palindrome two-pointers	two pointers	O(n^2)	Dec 25, 2022
Most popular video creator array-and-hashmap heap	array and hashmap heap	O(nlog(n))	Dec 25, 2022
Reward top k students array-and-hashmap	array and hashmap	O(nlog(n))	Dec 25, 2022
Take k of each character from left and right array-and-hashmap two-pointers	array and hashmap two pointers	O(n)	Dec 25, 2022
Beautiful array array-and-hashmap	array and hashmap	O(n)	Dec 24, 2022
Custom sort string array-and-hashmap	array and hashmap	O(n)	Dec 24, 2022
Domino and tromino tiling dynamic-programming	dynamic programming	O(n)	Dec 24, 2022
Number of distinct islands graph	graph	O(mn)	Dec 24, 2022
Valid triangle number greedy binary-search	greedy binary search	O(n^2)	Dec 24, 2022
Convert binary search tree to sorted doubly linked list linked-list tree	linked list tree	O(n)	Dec 23, 2022
Count good meals array-and-hashmap	array and hashmap	O(nlog(n))	Dec 23, 2022
Flatten a multilevel doubly linked list linked-list tree	linked list tree	O(n)	Dec 23, 2022
Check if there is a path with equal number of 0s and 1s dynamic-programming	dynamic programming	O(mn)	Dec 22, 2022
Largest values from labels greedy	greedy	O(nlogn)	Dec 22, 2022
Sum of distances in tree tree	tree	O(n)	Dec 22, 2022
Find distance in a binary tree tree	tree	O(n)	Dec 21, 2022
Largest merge of two strings greedy	greedy	O(n+m)	Dec 21, 2022
Maximal network rank graph	graph	O(n^2)	Dec 21, 2022
Possible bipartition graph	graph	O(n+m)	Dec 21, 2022
Backspace string compare stack	stack	O(n+m)	Dec 20, 2022
Longest mountain in array two-pointers	two pointers	O(n)	Dec 20, 2022
Minimum initial energy to finish tasks greedy	greedy	O(nlog(n))	Dec 20, 2022
Shifting letters array-and-hashmap	array and hashmap	O(n)	Dec 20, 2022
Ways to make a fair array array-and-hashmap	array and hashmap	O(n)	Dec 20, 2022
Binary tree longest consecutive sequence tree	tree	O(n)	Dec 19, 2022
Check if array pairs are divisible by k array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Clone binary tree with random pointer tree	tree	O(n)	Dec 19, 2022
Decode the message array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Delete n nodes after m nodes of a linked list linked-list	linked list	O(n)	Dec 19, 2022
Maximum number of books you can take stack	stack	O(n)	Dec 19, 2022
Path crossing array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Check if there is a valid parentheses string path dynamic-programming	dynamic programming	O(n^2)	Dec 18, 2022
Day of the year math-and-geometry	math and geometry	O(1)	Dec 18, 2022
Pancake sorting array-and-hashmap	array and hashmap	O(n^2)	Dec 18, 2022
Powerful integers math-and-geometry	math and geometry	O(n^2)	Dec 18, 2022
Add two integers math-and-geometry	math and geometry	O(1)	Dec 17, 2022
Apply discount to prices array-and-hashmap	array and hashmap	O(n)	Dec 17, 2022
Maximum sum score of array array-and-hashmap	array and hashmap	O(n)	Dec 17, 2022
Minimum rounds to complete all tasks greedy	greedy	O(n)	Dec 17, 2022
Number of boomerangs array-and-hashmap	array and hashmap	O(n^2)	Dec 17, 2022
Replace elements in an array array-and-hashmap	array and hashmap	O(n+m)	Dec 17, 2022
Root equals sum of children tree	tree	O(1)	Dec 17, 2022
Ternary expression parser stack	stack	O(n)	Dec 17, 2022
Encode number array-and-hashmap	array and hashmap	O(log(n))	Dec 16, 2022
Number of closed islands graph	graph	O(mn)	Dec 16, 2022
Widest pair of indices with equal range sum array-and-hashmap	array and hashmap	O(n)	Dec 16, 2022
Campus bikes II dynamic-programming	dynamic programming	O(2^n)	Dec 15, 2022
Append k integers with minimal sum greedy	greedy	O(nlog(n))	Dec 14, 2022
Count number of homogenous substrings array-and-hashmap	array and hashmap	O(n)	Dec 14, 2022
Minimum number of operations to move all balls to each box array-and-hashmap	array and hashmap	O(n)	Dec 14, 2022
Ugly number III math-and-geometry	math and geometry	O(log(n))	Dec 14, 2022
Check whether two strings are almost equivalent array-and-hashmap	array and hashmap	O(n)	Dec 13, 2022
Detect capital array-and-hashmap	array and hashmap	O(1)	Dec 13, 2022
Increasing subsequences backtracking	backtracking	O(n^2)	Dec 13, 2022
Letter case permutation backtracking	backtracking	O(2^n)	Dec 13, 2022
Moving average from data stream queue design	queue design	O(1)	Dec 13, 2022
Average waiting time intervals array-and-hashmap	intervals array and hashmap	O(n)	Dec 12, 2022
Longest square streak in an array greedy	greedy	O(nlog(n))	Dec 12, 2022
Longest univalue path tree	tree	O(n)	Dec 12, 2022
Lowest common ancestor of deepest leaves tree	tree	O(n)	Dec 12, 2022
Maximum level sum of a binary tree tree	tree	O(n)	Dec 12, 2022
Maximum nesting depth of two valid parentheses strings stack	stack	O(n)	Dec 12, 2022
Smallest subtree with all the deepest nodes tree	tree	O(n)	Dec 12, 2022
Best time to buy and sell stock with transaction fee dynamic-programming	dynamic programming	O(n)	Dec 11, 2022
Minimum cost to connect sticks heap	heap	O(nlog(n))	Dec 11, 2022
Remove nodes from linked list linked-list	linked list	O(n)	Dec 11, 2022
Removing stars from a string stack	stack	O(n)	Dec 11, 2022
Find the longest substring containing vowels in even counts array-and-hashmap	array and hashmap	O(n)	Dec 10, 2022
Maximum product of splitted binary tree tree	tree	O(n)	Dec 10, 2022
Partition array such that maximum difference is k greedy	greedy	O(nlog(n))	Dec 10, 2022
Valid palindrome IV array-and-hashmap two-pointers	array and hashmap two pointers	O(n)	Dec 10, 2022
Add two polynomials represented as linked lists linked-list	linked list	O(n)	Dec 9, 2022
Design hit counter design queue	design queue	O(n)	Dec 9, 2022
Longest substring with at least k repeating characters array-and-hashmap	array and hashmap	O(n)	Dec 9, 2022
Maximize the confusion of an exam sliding-window	sliding window	O(n)	Dec 9, 2022
Number of pairs of interchangeable rectangles array-and-hashmap	array and hashmap	O(n)	Dec 9, 2022
Find root of N-ary tree tree	tree	O(n)	Dec 8, 2022
Insert into a sorted circular linked list linked-list	linked list	O(n)	Dec 8, 2022
Maximum number of non overlapping subarrays with sum equals target greedy	greedy	O(n)	Dec 8, 2022
Range frequency queries binary-search design	binary search design	O(log(n))	Dec 8, 2022
Can you eat your favorite candy on your favorite day array-and-hashmap	array and hashmap	O(n)	Dec 7, 2022
Design tic tac toe design	design	O(1)	Dec 7, 2022
Maximum size subarray sum equals k array-and-hashmap	array and hashmap	O(n)	Dec 7, 2022
Minimum cost to buy apples graph	graph	O(nlog(n))	Dec 7, 2022
Number of subarrays having even product array-and-hashmap	array and hashmap	O(n)	Dec 7, 2022
Range sum of bst tree	tree	O(n)	Dec 7, 2022
Words within two edits of dictionary array-and-hashmap	array and hashmap	O(n^2)	Dec 7, 2022
Alert using same key card three or more times in a one hour period array-and-hashmap	array and hashmap	O(nlog(n))	Dec 6, 2022
Describe the painting array-and-hashmap	array and hashmap	O(nlog(n))	Dec 6, 2022
Encode and decode strings design	design	O(n)	Dec 6, 2022
largest-bst-subtree tree	tree	O(n^2)	Dec 6, 2022
Number of ways to buy pens and pencils math-and-geometry	math and geometry	O(n)	Dec 6, 2022
Find center of star graph graph	graph	O(1)	Dec 5, 2022
Find k pairs with smallest sums heap	heap	O(klog(n))	Dec 5, 2022
Fraction to recurring decimal math-and-geometry	math and geometry	O(n)	Dec 5, 2022
Middle of the linked list linked-list	linked list	O(n)	Dec 5, 2022
Minimum score of a path between two cities graph	graph	O(n)	Dec 5, 2022
One edit distance array-and-hashmap	array and hashmap	O(n)	Dec 5, 2022
Remove interval intervals	intervals	O(n)	Dec 5, 2022
Wiggle sort array-and-hashmap	array and hashmap	O(n)	Dec 5, 2022
Implement trie II (prefix tree) trie design	trie design	O(n)	Dec 4, 2022
Minimum average difference array-and-hashmap	array and hashmap	O(n)	Dec 4, 2022
Minimum number of steps to make two strings anagram II array-and-hashmap	array and hashmap	O(n)	Dec 4, 2022
Minimum number of steps to make two strings anagram array-and-hashmap	array and hashmap	O(n)	Dec 4, 2022
Find k length substrings with no repeated characters sliding-window	sliding window	O(n)	Dec 3, 2022
Longest string chain dynamic-programming	dynamic programming	O(n^2)	Dec 3, 2022
Longest substring with at most k distinct characters sliding-window	sliding window	O(n)	Dec 3, 2022
Longest substring with at most two distinct characters sliding-window	sliding window	O(n)	Dec 3, 2022
Number of connected components in an undirected graph graph	graph	O(n)	Dec 3, 2022
Number of subarrays with gcd equal to k math-and-geometry	math and geometry	O(n^2)	Dec 3, 2022
Number of subarrays with lcm equal to k math-and-geometry	math and geometry	O(n^2)	Dec 3, 2022
Connecting cities with minimum cost graph	graph	O(nlog(n))	Dec 2, 2022
Determine if two strings are close array-and-hashmap	array and hashmap	O(n)	Dec 2, 2022
Minimum cost to reach city with discounts graph	graph	O(nlog(n))	Dec 2, 2022
Nth digit math-and-geometry	math and geometry	O(log(n))	Dec 2, 2022
Previous permutation with one swap greedy	greedy	O(n)	Dec 2, 2022
Search in a sorted array of unknown size binary-search	binary search	O(log(n))	Dec 2, 2022
Determine if string halves are alike array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Evaluate the bracket pairs of a string array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Factorial trailing zeroes math-and-geometry	math and geometry	O(log(n))	Dec 1, 2022
Majority element II array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Path sum IV tree	tree	O(n)	Dec 1, 2022
Single row keyboard array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Bitwise xor of all pairings bit-manipulation	bit manipulation	O(n)	Nov 30, 2022
Count nodes equal to average of subtree tree	tree	O(n)	Nov 30, 2022
Find all lonely numbers in the array array-and-hashmap	array and hashmap	O(n)	Nov 30, 2022
Find leaves of binary tree tree	tree	O(n)	Nov 30, 2022
Fizz buzz array-and-hashmap	array and hashmap	O(n)	Nov 30, 2022
Maximum average subtree tree	tree	O(n)	Nov 30, 2022
Maximum split of positive even integers greedy	greedy	O(n)	Nov 30, 2022
Nim game math-and-geometry	math and geometry	O(1)	Nov 30, 2022
Partitioning into minimum number of deci binary numbers greedy	greedy	O(n)	Nov 30, 2022
Recover a tree from preorder traversal tree	tree	O(n)	Nov 30, 2022
Remove duplicates from an unsorted linked list linked-list	linked list	O(n)	Nov 30, 2022
Sparse matrix multiplication math-and-geometry	math and geometry	O(n^3)	Nov 30, 2022
Unique number of occurrences array-and-hashmap	array and hashmap	O(n)	Nov 30, 2022
Unique word abbreviation array-and-hashmap design	array and hashmap design	O(n)	Nov 30, 2022
Verify preorder sequence in binary search tree tree	tree	—	Nov 30, 2022
Count of smaller numbers after self binary-search	binary search	O(nlog(n))	Nov 29, 2022
Count univalue subtrees tree	tree	O(n)	Nov 29, 2022
Generate a string with characters that have odd counts array-and-hashmap	array and hashmap	O(n)	Nov 29, 2022
Inorder successor in BST tree	tree	O(h)	Nov 29, 2022
Longest subarray of 1s after deleting one element two-pointers	two pointers	O(n)	Nov 29, 2022
Print immutable linked list in reverse linked-list stack	linked list stack	O(n)	Nov 29, 2022
Reverse words in a string II array-and-hashmap	array and hashmap	O(n)	Nov 29, 2022
Valid palindrome III dynamic-programming	dynamic programming	O(n^2)	Nov 29, 2022
Binary tree vertical order traversal tree	tree	O(n)	Nov 28, 2022
Count nodes equal to sum of descendants tree	tree	O(n)	Nov 28, 2022
Count number of bad pairs dynamic-programming	dynamic programming	O(n)	Nov 28, 2022
Count pairs in two arrays binary-search	binary search	O(nlogn)	Nov 28, 2022
Design hashset design array-and-hashmap	design array and hashmap	O(1)	Nov 28, 2022
Design phone directory design	design	O(1)	Nov 28, 2022
Find players with zero or one losses array-and-hashmap	array and hashmap	O(nlog(n))	Nov 28, 2022
Minimize product sum of two arrays greedy	greedy	O(nlog(n))	Nov 28, 2022
Remove zero sum consecutive nodes from linked list linked-list	linked list	O(n)	Nov 28, 2022
Shortest word distance array-and-hashmap	array and hashmap	O(n)	Nov 28, 2022
Validate binary tree nodes tree	tree	O(n)	Nov 28, 2022
Arithmetic slices II subsequence dynamic-programming	dynamic programming	O(n^2)	Nov 27, 2022
Arithmetic slices dynamic-programming	dynamic programming	O(n)	Nov 27, 2022
Binary tree upside down tree	tree	O(n)	Nov 27, 2022
Check if word is valid after substitutions stack	stack	O(n)	Nov 26, 2022
Design browser history linked-list	linked list	O(n)	Nov 26, 2022
Find smallest common element in all rows array-and-hashmap	array and hashmap	O(n)	Nov 26, 2022
Maximum number of coins you can get greedy queue	greedy queue	O(nlog(n))	Nov 26, 2022
Maximum twin sum of a linked list linked-list	linked list	O(n)	Nov 26, 2022
Meeting rooms III intervals heap	intervals heap	—	Nov 26, 2022
Minimize maximum pair sum in array greedy	greedy	O(nlog(n))	Nov 26, 2022
Next greater node in linked list linked-list stack	linked list stack	O(n)	Nov 26, 2022
Spiral matrix IV linked-list	linked list	O(mn)	Nov 26, 2022
Strobogrammatic number array-and-hashmap	array and hashmap	O(n)	Nov 26, 2022
Add two numbers II linked-list stack	linked list stack	O(n)	Nov 25, 2022
Find greatest common divisor of array math-and-geometry	math and geometry	O(nlog(n))	Nov 25, 2022
Sum of subarray minimums stack	stack	O(n)	Nov 25, 2022
Swapping nodes in a linked list linked-list	linked list	O(n)	Nov 25, 2022
Complement of base 10 integer bit-maniuplation	bit maniuplation	O(1)	Nov 24, 2022
Minimum number of arrows to burst balloons greedy	greedy	O(nlog(n))	Nov 24, 2022
Stone game VII dynamic-programming	dynamic programming	O(n^2)	Nov 24, 2022
The employee that worked on the longest task array-and-hashmap	array and hashmap	O(n)	Nov 24, 2022
Broken calculator greedy	greedy	O(log(n))	Nov 23, 2022
Delete duplicate folders in system trie	trie	O(nlog(n))	Nov 23, 2022
Final prices with a special discount in a shop stack	stack	O(n)	Nov 23, 2022
Integer to english words array-and-hashmap greedy	array and hashmap greedy	O(log(n))	Nov 23, 2022
Power of two math-and-geometry bit-maniuplation	math and geometry bit maniuplation	O(log(n))	Nov 23, 2022
Rabbits in forest math-and-geometry	math and geometry	O(n)	Nov 23, 2022
Sliding window median sliding-window	sliding window	O(nlog(n))	Nov 23, 2022
odd-even-jump dynamic-programming stack	dynamic programming stack	O(nlog(n))	Nov 22, 2022
132 pattern stack	stack	O(n)	Nov 22, 2022
Boats to save people two-pointers	two pointers	O(nlog(n))	Nov 22, 2022
Number of ways to paint N×3 grid dynamic-programming	dynamic programming	O(n)	Nov 22, 2022
Process tasks using servers heap	heap	O(nlog(n))	Nov 22, 2022
Random pick index array-and-hashmap design	array and hashmap design	O(1)	Nov 22, 2022
Shuffle an array math-and-geometry design	math and geometry design	O(n)	Nov 22, 2022
Sort colors two-pointers array-and-hashmap	two pointers array and hashmap	O(n)	Nov 22, 2022
Split array largest sum binary-search	binary search	—	Nov 22, 2022
Base 7 math-and-geometry	math and geometry	O(log(n))	Nov 21, 2022
Camelcase matching two-pointers queue	two pointers queue	O(n)	Nov 21, 2022
design linked list linked-list design	linked list design	—	Nov 21, 2022
Linked list in binary tree linked-list tree	linked list tree	O(n)	Nov 21, 2022
Maximum sum circular subarray array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
Minimum addition to make integer beautiful math-and-geometry	math and geometry	O(log(n))	Nov 21, 2022
Nearest exit from entrance in maze graph	graph	O(mn)	Nov 21, 2022
Number of operations to make network connected graph	graph	O(n)	Nov 21, 2022
Sum of absolute differences in a sorted array array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
Total cost to hire k workers heap	heap	O(nlog(n))	Nov 21, 2022
Vowel spellchecker array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
All nodes distance k in binary tree tree	tree	O(n)	Nov 20, 2022
Find all duplicates in an array array-and-hashmap	array and hashmap	O(n)	Nov 20, 2022
Maximum length of pair chain greedy	greedy	O(nlog(n))	Nov 20, 2022
Number of orders in the backlog heap	heap	O(nlog(n))	Nov 20, 2022
Number of ways to arrive at destination graph	graph	O(nlog(n))	Nov 20, 2022
Path with maximum probability graph	graph	O(nlog(n))	Nov 20, 2022
Reverse prefix of word array-and-hashmap	array and hashmap	O(n)	Nov 20, 2022
Shopping offers dynamic-programming	dynamic programming	O(n^m)	Nov 20, 2022
Widest vertical area between two points containing no points array-and-hashmap	array and hashmap	O(nlogn)	Nov 20, 2022
Binary subarrays with sum array-and-hashmap sliding-window	array and hashmap sliding window	O(n)	Nov 19, 2022
Erect the fence math-and-geometry	math and geometry	O(nlogn)	Nov 19, 2022
Maximum product after k increments heap	heap	O(klog(n))	Nov 19, 2022
Number of ways to split array array-and-hashmap	array and hashmap	O(n)	Nov 19, 2022
First letter to appear twice array-and-hashmap	array and hashmap	O(n)	Nov 18, 2022
Frog position after t seconds graph	graph	O(n)	Nov 18, 2022
Linked list components linked-list	linked list	O(n)	Nov 18, 2022
Find the highest altitude array-and-hashmap	array and hashmap	O(n)	Nov 17, 2022
Finding the users active minutes array-and-hashmap	array and hashmap	O(n)	Nov 17, 2022
Number of digit one math-and-geometry	math and geometry	O(log(n))	Nov 17, 2022
Rectangle area math-and-geometry	math and geometry	O(1)	Nov 17, 2022
Symmetric tree tree	tree	O(n)	Nov 17, 2022
Construct binary search tree from preorder traversal tree	tree	O(n)	Nov 16, 2022
Count days spent together array-and-hashmap	array and hashmap	O(1)	Nov 16, 2022
Delete nodes and return forest tree	tree	O(n)	Nov 16, 2022
Insert into a binary search tree tree	tree	O(n)	Nov 16, 2022
Making file names unique array-and-hashmap	array and hashmap	O(n)	Nov 16, 2022
Minimum distance to the target element array-and-hashmap	array and hashmap	O(n)	Nov 16, 2022
Minimum time visiting all points greedy	greedy	O(n)	Nov 16, 2022
Path in zigzag labelled binary tree tree	tree	O(log(n))	Nov 16, 2022
Shortest subarray to be removed to make array sorted two-pointers	two pointers	O(n)	Nov 16, 2022
Trim a binary search tree tree	tree	O(n)	Nov 16, 2022
Binary tree tilt tree	tree	O(n)	Nov 15, 2022
Count of matches in tournament math-and-geometry	math and geometry	O(log(n))	Nov 15, 2022
Dungeon game dynamic-programming	dynamic programming	O(mn)	Nov 15, 2022
Find duplicate subtrees tree	tree	O(n)	Nov 15, 2022
Find mode in binary search tree tree	tree	O(n)	Nov 15, 2022
Longest substring of all vowels in order sliding-window	sliding window	O(n)	Nov 15, 2022
Make two arrays equal by reversing subarrays array-and-hashmap	array and hashmap	O(nlog(n))	Nov 15, 2022
Maximum area of a piece of cake after horizontal and vertical cuts greedy	greedy	O(nlogn+mlogm)	Nov 15, 2022
Maximum width of binary tree tree	tree	O(n)	Nov 15, 2022
Maximum xor after operations bit-manipulation	bit manipulation	O(n)	Nov 15, 2022
Most frequent subtree sum tree	tree	O(n)	Nov 15, 2022
Path sum III dynamic-programming backtracking tree	dynamic programming backtracking tree	O(n)	Nov 15, 2022
Merge strings alternately array-and-hashmap	array and hashmap	O(n+m)	Nov 14, 2022
Most stones removed with same row or column graph	graph	O(n)	Nov 14, 2022
Maximum frequency stack stack design	stack design	—	Nov 13, 2022
Number of subarrays with bounded maximum two-pointers	two pointers	O(n)	Nov 13, 2022
Leaf similar trees tree	tree	O(n+m)	Nov 12, 2022
Least number of unique integers after k removals heap	heap	O(n+klog(n))	Nov 12, 2022
Number of zero filled subarrays math-and-geometry	math and geometry	O(n)	Nov 12, 2022
Count numbers with unique digits math-and-geometry	math and geometry	O(n)	Nov 11, 2022
Removing minimum number of magic beans array-and-hashmap	array and hashmap	O(nlog(n))	Nov 11, 2022
Find peak element binary-search	binary search	O(log(n))	Nov 10, 2022
Maximum nesting depth of the parentheses stack	stack	O(n)	Nov 10, 2022
Remove all adjacent duplicates in string II stack	stack	O(n)	Nov 10, 2022
Remove all adjacent duplicates in string stack	stack	O(n)	Nov 10, 2022
Score of parentheses stack	stack	O(n)	Nov 10, 2022
Triangle dynamic-programming	dynamic programming	O(n^2)	Nov 10, 2022
Distribute candies array-and-hashmap	array and hashmap	O(n)	Nov 9, 2022
Online stock span stack	stack	O(n)	Nov 9, 2022
Average value of even numbers that are divisible by three math-and-geometry	math and geometry	O(n)	Nov 8, 2022
Knight dialer dynamic-programming	dynamic programming	O(n)	Nov 8, 2022
Make the string great stack	stack	O(n)	Nov 8, 2022
Minimum money required before transactions greedy	greedy	O(n)	Nov 8, 2022
Pascals triangle II array-and-hashmap	array and hashmap	O(n)	Nov 8, 2022
Array with elements not equal to average of neighbors two-pointers	two pointers	O(nlogn)	Nov 7, 2022
Maximum 69 number array-and-hashmap	array and hashmap	O(n)	Nov 7, 2022
Number of subsequences that satisfy the given sum condition two-pointers	two pointers	O(nlogn)	Nov 7, 2022
Wiggle sort II array-and-hashmap	array and hashmap	O(nlogn)	Nov 7, 2022
Check completeness of a binary tree tree	tree	O(n)	Nov 6, 2022
Design an ordered stream design	design	O(n)	Nov 6, 2022
Jewels and stones array-and-hashmap	array and hashmap	O(n)	Nov 6, 2022
Minimum number of vertices to reach all nodes graph	graph	O(n)	Nov 6, 2022
Orderly queue array-and-hashmap	array and hashmap	O(n^n)	Nov 6, 2022
Sort integers by the number of 1 bits bit-manipulation	bit manipulation	O(nlogn)	Nov 6, 2022
Counting words with a given prefix array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Find all numbers disappeared in an array array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Find pivot index array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Majority element array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Maximum number of balloons array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Merge in between linked lists linked-list	linked list	O(n)	Nov 5, 2022
Next greater element II stack	stack	O(n)	Nov 5, 2022
Sum of beauty of all substrings array-and-hashmap	array and hashmap	O(n^2)	Nov 5, 2022
The k strongest values in an array array-and-hashmap	array and hashmap	O(nlogn)	Nov 5, 2022
Word pattern array-and-hashmap	array and hashmap	O(n)	Nov 5, 2022
Encode and decode tinyurl design	design	O(1)	Nov 4, 2022
Maximum profit in job scheduling dynamic-programming intervals	dynamic programming intervals	O(n^2)	Nov 4, 2022
Maximum score from removing stones greedy	greedy	O(n)	Nov 4, 2022
Partition array into three parts with equal sum greedy	greedy	O(n)	Nov 4, 2022
Reverse vowels of a string stack	stack	O(n)	Nov 4, 2022
Longest palindrome by concatenating two letter words array-and-hashmap	array and hashmap	O(n)	Nov 3, 2022
Smallest good base math-and-geometry	math and geometry	O(log(n)^2)	Nov 3, 2022
Count items matching a rule array-and-hashmap	array and hashmap	O(n)	Nov 2, 2022
Intersection of two arrays intervals	intervals	O(n)	Nov 2, 2022
Largest 3 same digit number in string array-and-hashmap	array and hashmap	O(n)	Nov 2, 2022
Letter tile possibilities backtracking	backtracking	O(n!)	Nov 1, 2022
Minimum absolute difference in bst tree	tree	O(n)	Nov 1, 2022
Minimum swaps to group all 1s together II sliding-window	sliding window	O(n)	Nov 1, 2022
Where will the ball fall array-and-hashmap	array and hashmap	O(r*c)	Nov 1, 2022
Find all possible recipes from given supplies graph	graph	O(n)	Oct 31, 2022
Optimal division math-and-geometry	math and geometry	O(n)	Oct 31, 2022
Pairs of songs with total durations divisible by 60 math-and-geometry	math and geometry	O(n)	Oct 31, 2022
Toeplitz matrix array-and-hashmap	array and hashmap	O(n)	Oct 31, 2022
Divide array into equal pairs array-and-hashmap	array and hashmap	O(n)	Oct 30, 2022
Shortest path in a grid with obstacles elimination graph	graph	O(mn)	Oct 30, 2022
Valid number array-and-hashmap	array and hashmap	O(n)	Oct 30, 2022
Earliest possible day of full bloom greedy	greedy	O(nlogn)	Oct 29, 2022
Most frequent number following key in an array array-and-hashmap	array and hashmap	O(n)	Oct 29, 2022
Search in a binary search tree tree	tree	O(n)	Oct 29, 2022
All elements in two binary search trees tree	tree	O(n1+n2)	Oct 28, 2022
Fruit into baskets sliding-window	sliding window	O(n)	Oct 28, 2022
Integer replacement dynamic-programming	dynamic programming	O(n)	Oct 28, 2022
Max consecutive ones III sliding-window	sliding window	O(n)	Oct 28, 2022
Max consecutive ones sliding-window	sliding window	O(n)	Oct 28, 2022
Replace the substring for balanced string sliding-window	sliding window	O(n)	Oct 28, 2022
Sum of number and its reverse math-and-geometry	math and geometry	O(n)	Oct 28, 2022
Count good numbers math-and-geometry	math and geometry	O(1)	Oct 27, 2022
Image overlap array-and-hashmap	array and hashmap	O(n^2)	Oct 27, 2022
Predict the winner dynamic-programming	dynamic programming	O(n)	Oct 27, 2022
XOR queries of a subarray bit-manipulation	bit manipulation	O(n)	Oct 27, 2022
Groups of special equivalent strings array-and-hashmap	array and hashmap	O(n*klog(k))	Oct 26, 2022
Kth missing positive number binary-search	binary search	O(n)	Oct 26, 2022
Longest uploaded prefix heap design	heap design	O(n)	Oct 26, 2022
Maximum number of pairs in array array-and-hashmap	array and hashmap	O(n)	Oct 26, 2022
Minesweeper graph	graph	O(n^2)	Oct 26, 2022
Shortest bridge graph	graph	O(n^2)	Oct 26, 2022
Check if two string arrays are equivalent array-and-hashmap	array and hashmap	O(n)	Oct 25, 2022
Escape the ghosts math-and-geometry	math and geometry	O(n)	Oct 25, 2022
Reverse odd levels of binary tree tree	tree	O(n)	Oct 25, 2022
Serialize and deserialize bst tree design	tree design	O(n)	Oct 25, 2022
Maximum length of a concatenated string with unique characters array-and-hashmap	array and hashmap	O(n^2)	Oct 24, 2022
Open the lock graph	graph	O(n^2)	Oct 24, 2022
Can place flowers greedy	greedy	O(n)	Oct 23, 2022
Integer break dynamic-programming	dynamic programming	O(n^2)	Oct 23, 2022
Set mismatch math-and-geometry	math and geometry	O(n)	Oct 23, 2022
Destination city array-and-hashmap	array and hashmap	O(n)	Oct 22, 2022
Minimum number of operations to convert time greedy	greedy	O(1)	Oct 22, 2022
Contains duplicate II array-and-hashmap	array and hashmap	O(n)	Oct 21, 2022
Isomorphic strings array-and-hashmap	array and hashmap	O(n)	Oct 21, 2022
Unique email addresses array-and-hashmap	array and hashmap	O(n)	Oct 21, 2022
Maximum points you can obtain from cards greedy	greedy	O(n)	Oct 20, 2022
Number of valid move combinations on chessboard backtracking	backtracking	O(n^2)	Oct 20, 2022
Map sum pairs trie	trie	O(n)	Oct 19, 2022
Minimum operations to halve array sum heap	heap	O(nlog(n))	Oct 19, 2022
Queries on a permutation with key array-and-hashmap	array and hashmap	O(n^2)	Oct 19, 2022
Short encoding of words trie	trie	O(n)	Oct 19, 2022
Reduction operations to make the array elements equal greedy	greedy	O(nlog(n))	Oct 18, 2022
Best sightseeing pair array-and-hashmap	array and hashmap	O(n)	Oct 17, 2022
Convert binary number in a linked list to integer linked-list	linked list	O(n)	Oct 16, 2022
Delete leaves with a given value tree	tree	O(n)	Oct 16, 2022
Find numbers with even number of digits array-and-hashmap	array and hashmap	O(n^2)	Oct 16, 2022
Minimum difficulty of a job schedule dynamic-programming	dynamic programming	O(n^2*d)	Oct 16, 2022
String compression II dynamic-programming	dynamic programming	O(n*k)	Oct 15, 2022
Delete the middle node of a linked list linked-list	linked list	O(n)	Oct 14, 2022
Find missing observations math-and-geometry	math and geometry	O(m+n)	Oct 13, 2022
Find positive integer solution for a given equation math-and-geometry	math and geometry	O(x+y)	Oct 13, 2022
Shift 2d grid math-and-geometry	math and geometry	O(m*n)	Oct 13, 2022
Determine whether matrix can be obtained by rotation array-and-hashmap	array and hashmap	O(n^2)	Oct 12, 2022
Largest perimeter triangle math-and-geometry	math and geometry	O(nlogn)	Oct 12, 2022
Increasing triplet subsequence greedy	greedy	O(n)	Oct 11, 2022
Number of recent calls queue design	queue design	O(n)	Oct 11, 2022
Break a palindrome array-and-hashmap	array and hashmap	O(n)	Oct 10, 2022
Convert bst to greater tree tree	tree	O(n)	Oct 9, 2022
Find bottom left tree value tree	tree	O(n)	Oct 9, 2022
Flip equivalent binary trees tree	tree	O(n)	Oct 9, 2022
Frequency of the most frequent element sliding-window	sliding window	O(nlogn)	Oct 9, 2022
Guess number higher or lower binary-search	binary search	O(log(n))	Oct 9, 2022
Two sum IV input is a bst tree	tree	O(n)	Oct 9, 2022
Find all anagrams in a string array-and-hashmap	array and hashmap	O(n*m)	Oct 8, 2022
Find the index of the first occurrence in a string sliding-window	sliding window	O(n)	Oct 8, 2022
Remove element array-and-hashmap	array and hashmap	O(n)	Oct 8, 2022
Unique length 3 palindromic subsequences array-and-hashmap	array and hashmap	O(n)	Oct 8, 2022
Reverse linked list II linked-list	linked list	O(n)	Oct 7, 2022
Search insert position binary-search	binary search	O(log(n))	Oct 7, 2022
Single threaded cpu heap	heap	O(nlog(n))	Oct 7, 2022
Baseball game stack	stack	O(n)	Oct 6, 2022
Is subsequence two-pointers	two pointers	O(n)	Oct 6, 2022
Length of last word two-pointers	two pointers	O(n)	Oct 6, 2022
Longest common prefix array-and-hashmap	array and hashmap	O(n^m)	Oct 6, 2022
Merge two binary trees tree	tree	O(n)	Oct 6, 2022
Replace elements with greatest element on right side array-and-hashmap	array and hashmap	O(n)	Oct 6, 2022
Add one row to tree tree	tree	O(n)	Oct 5, 2022
Add binary bit-manipulation	bit manipulation	O(max(n, m))	Oct 4, 2022
Delete node in a linked list linked-list	linked list	O(1)	Oct 4, 2022
N-queens II backtracking	backtracking	O(n^2)	Oct 4, 2022
Palindrome number math-and-geometry	math and geometry	O(n)	Oct 4, 2022
Remove covered intervals intervals	intervals	O(nlog(n))	Oct 4, 2022
Ugly number math-and-geometry	math and geometry	O(n)	Oct 4, 2022
Asteroid collision stack	stack	O(n)	Oct 3, 2022
Minimum time to make rope colorful greedy	greedy	O(n)	Oct 3, 2022
Minimum difference between highest and lowest of k scores sliding-window	sliding window	O(nlog(n))	Oct 2, 2022
Move zeroes two-pointers	two pointers	O(n)	Oct 2, 2022
Number of dice rolls with target sum dynamic-programming	dynamic programming	O(nkt)	Oct 2, 2022
Rotate array two-pointers	two pointers	O(n)	Oct 2, 2022
Intersection of two linked lists linked-list	linked list	O(n)	Oct 1, 2022
Merge sorted array two-pointers	two pointers	O(n)	Oct 1, 2022
Reverse string two-pointers	two pointers	O(n)	Oct 1, 2022
Valid palindrome II two-pointers	two pointers	O(n)	Oct 1, 2022
Destroying asteroids greedy	greedy	O(nlog(n))	Sep 30, 2022
Dota2 senate greedy queue	greedy queue	O(n)	Sep 30, 2022
Reveal cards in increasing order queue	queue	O(nlog(n))	Sep 30, 2022
Word break II trie backtracking	trie backtracking	O(n^2)	Sep 30, 2022
Design front middle back queue queue design	queue design	O(1)	Sep 29, 2022
Find the winner of the circular game queue	queue	O(n*k)	Sep 29, 2022
Flood fill graph	graph	O(n)	Sep 28, 2022
Product of the last k numbers queue design	queue design	O(1)	Sep 28, 2022
Bulb switcher math-and-geometry	math and geometry	O(1)	Sep 27, 2022
Design circular deque queue design	queue design	O(1)	Sep 27, 2022
Flatten nested list iterator queue design	queue design	O(n)	Sep 27, 2022
Push dominoes two-pointers	two pointers	O(n^2)	Sep 27, 2022
Reverse string II two-pointers	two pointers	O(n)	Sep 27, 2022
Strictly palindromic number math-and-geometry	math and geometry	O(n^2)	Sep 27, 2022
Satisfiability of equality equations graph	graph	O(n^2)	Sep 26, 2022
Count nice pairs in an array array-and-hashmap	array and hashmap	O(n)	Sep 25, 2022
Concatenation of consecutive binary numbers bit-manipulation	bit manipulation	O(n)	Sep 23, 2022
Partition to k equal sum subsets backtracking	backtracking	O(k * 2^n)	Sep 23, 2022
Reverse words in a string III array-and-hashmap	array and hashmap	O(n)	Sep 22, 2022
Sum of even numbers after queries array-and-hashmap	array and hashmap	O(n)	Sep 21, 2022
Find duplicate file in system array-and-hashmap	array and hashmap	O(n)	Sep 19, 2022
Number of sub arrays with odd sum math-and-geometry	math and geometry	O(n)	Sep 18, 2022
Deepest leaves sum tree	tree	O(n)	Sep 17, 2022
Iterator for combination design backtracking	design backtracking	O(nCk)	Sep 17, 2022
Design an atm machine greedy design	greedy design	O(1)	Sep 16, 2022
Finding pairs with a certain sum design	design	O(n+m)	Sep 16, 2022
Maximum score from performing multiplication operations dynamic-programming	dynamic programming	O(n*m)	Sep 16, 2022
Minimum genetic mutation graph	graph	O(n)	Sep 16, 2022
Minimum insertions to balance a parentheses string stack greedy	stack greedy	O(n)	Sep 16, 2022
Stone game dynamic-programming	dynamic programming	O(n^2)	Sep 16, 2022
Find original array from doubled array array-and-hashmap	array and hashmap	O(nlog(n))	Sep 15, 2022
Validate ip address array-and-hashmap	array and hashmap	O(1)	Sep 15, 2022
Insufficient nodes in root to leaf paths tree	tree	O(n)	Sep 14, 2022
Pseudo palindromic paths in a binary tree backtracking tree	backtracking tree	O(n)	Sep 14, 2022
Spiral matrix II math-and-geometry	math and geometry	O(n)	Sep 14, 2022
Is graph bipartite graph	graph	O(n)	Sep 13, 2022
Range sum query immutable design	design	O(n)	Sep 13, 2022
Reorder data in log files array-and-hashmap	array and hashmap	O(nlog(n))	Sep 13, 2022
UTF-8 validation bit-manipulation	bit manipulation	O(n)	Sep 13, 2022
Bag of tokens two-pointers	two pointers	O(nlog(n))	Sep 12, 2022
Different ways to add parentheses dynamic-programming	dynamic programming	O(n)	Sep 12, 2022
Elimination game math-and-geometry	math and geometry	O(n)	Sep 12, 2022
Longest word in dictionary trie	trie	O(n)	Sep 12, 2022
Sender with largest word count array-and-hashmap	array and hashmap	O(nlog(n))	Sep 12, 2022
Find the city with the smallest number of neighbors at a threshold distance graph	graph	O(n^3)	Sep 11, 2022
Max sum of a pair with equal sum of digits array-and-hashmap	array and hashmap	O(n)	Sep 11, 2022
Maximum difference between node and ancestor tree	tree	O(n)	Sep 11, 2022
Maximum performance of a team heap	heap	O(nlog(n))	Sep 11, 2022
Minimum falling path sum dynamic-programming	dynamic programming	O(n*m)	Sep 11, 2022
Number of restricted paths from first to last node graph	graph	O(elog(v))	Sep 11, 2022
Best time to buy and sell stock II dynamic-programming	dynamic programming	O(n)	Sep 10, 2022
Best time to buy and sell stock III dynamic-programming	dynamic programming	O(n)	Sep 10, 2022
Best time to buy and sell stock IV dynamic-programming	dynamic programming	O(n)	Sep 10, 2022
Coloring a border graph	graph	O(n)	Sep 10, 2022
Count and say array-and-hashmap	array and hashmap	O(n)	Sep 10, 2022
Island perimeter graph	graph	O(n)	Sep 10, 2022
Maximum binary tree II tree	tree	O(n)	Sep 10, 2022
Maximum binary tree tree	tree	O(n)	Sep 10, 2022
Partition array according to given pivot array-and-hashmap	array and hashmap	O(n)	Sep 10, 2022
Wildcard matching dynamic-programming	dynamic programming	O(n*m)	Sep 10, 2022
Design a food rating system heap design	heap design	O(nlog(n))	Sep 9, 2022
Minimum number of swaps to make the string balanced stack	stack	O(n)	Sep 9, 2022
Peeking iterator design	design	O(1)	Sep 9, 2022
Remove linked list elements linked-list	linked list	O(n)	Sep 9, 2022
The number of weak characters in the game heap	heap	O(nlog(n))	Sep 9, 2022
Tuple with same product array-and-hashmap	array and hashmap	O(n^2)	Sep 9, 2022
Build an array with stack operations two-pointers	two pointers	O(n)	Sep 8, 2022
Combination sum III backtracking	backtracking	O(2^n)	Sep 8, 2022
Find k closest elements heap	heap	O(nlog(k))	Sep 8, 2022
Maximum erasure value sliding-window	sliding window	O(n)	Sep 8, 2022
Minimum consecutive cards to pick up sliding-window	sliding window	O(n)	Sep 8, 2022
Repeated dna sequences sliding-window	sliding window	O(n)	Sep 8, 2022
Robot bounded in circle math-and-geometry	math and geometry	O(n)	Sep 8, 2022
Construct string from binary tree tree	tree	O(n)	Sep 7, 2022
Keys and rooms graph	graph	O(n)	Sep 7, 2022
Print binary tree tree	tree	O(n)	Sep 7, 2022
Binary tree pruning tree	tree	O(n)	Sep 6, 2022
Design a stack with increment operation design stack	design stack	O(1)	Sep 6, 2022
H-index II array-and-hashmap	array and hashmap	O(log(n))	Sep 6, 2022
H-index array-and-hashmap	array and hashmap	O(n)	Sep 6, 2022
Implement magic dictionary trie design	trie design	O(n^2)	Sep 6, 2022
Lexicographical numbers graph	graph	O(nlog(n))	Sep 6, 2022
Linked list random node linked-list	linked list	O(n)	Sep 6, 2022
Merge nodes in between zeros linked-list	linked list	O(n)	Sep 6, 2022
Query kth smallest trimmed number heap	heap	O(q*nlog(n))	Sep 6, 2022
Remove stones to minimize the total heap	heap	—	Sep 6, 2022
Replace words trie	trie	O(n*k)	Sep 6, 2022
Reverse words in a string array-and-hashmap	array and hashmap	O(n)	Sep 6, 2022
Seat reservation manager heap	heap	O(n)	Sep 6, 2022
Smallest number in infinite set heap	heap	O(nlog(n))	Sep 6, 2022
Sort an array array-and-hashmap	array and hashmap	O(nlog(n))	Sep 6, 2022
Sort characters by frequency array-and-hashmap	array and hashmap	O(nlog(n))	Sep 6, 2022
All ancestors of a node in a directed acyclic graph graph	graph	O(n^2)	Sep 5, 2022
Basic calculator II stack	stack	O(n)	Sep 5, 2022
Basic calculator III stack	stack	O(n)	Sep 5, 2022
Basic calculator stack	stack	O(n)	Sep 5, 2022
Battleships in a board graph	graph	O(n)	Sep 5, 2022
Count primes math-and-geometry	math and geometry	—	Sep 5, 2022
Course schedule IV graph	graph	O(q*(n+p))	Sep 5, 2022
House robber III graph	graph	O(n)	Sep 5, 2022
Linked list cycle II linked-list	linked list	O(n)	Sep 5, 2022
Longest absolute file path stack	stack	O(n)	Sep 5, 2022
Number of enclaves graph	graph	O((m*n)^2)	Sep 5, 2022
Path sum II backtracking	backtracking	O(n)	Sep 5, 2022
Remove duplicate letters stack	stack	O(n)	Sep 5, 2022
Restore ip addresses backtracking	backtracking	O(n^2)	Sep 5, 2022
Search in rotated sorted array II binary-search	binary search	O(log(n))	Sep 5, 2022
Single number II bit-manipulation	bit manipulation	O(n)	Sep 5, 2022
Single number III bit-manipulation	bit manipulation	O(n)	Sep 5, 2022
Sort list linked-list	linked list	O(nlog(n))	Sep 5, 2022
Amount of time for binary tree to be infected tree	tree	O(n)	Sep 4, 2022
Binary search tree iterator tree	tree	O(n)	Sep 4, 2022
Binary tree level order traversal II tree	tree	O(n)	Sep 4, 2022
Binary tree zigzag level order traversal tree	tree	O(n)	Sep 4, 2022
Construct binary tree from inorder and postorder traversal tree	tree	O(n)	Sep 4, 2022
Convert sorted list to binary search tree tree	tree	O(n)	Sep 4, 2022
Count complete tree nodes tree	tree	O(log(n))	Sep 4, 2022
delete-node-in-a-bst tree	tree	O(log(n))	Sep 4, 2022
Evaluate division graph	graph	O(n^2*q)	Sep 4, 2022
Populating next right pointers in each node II tree	tree	O(n)	Sep 4, 2022
Populating next right pointers in each node tree	tree	O(n)	Sep 4, 2022
Recover binary search tree tree	tree	O(nlog(n))	Sep 4, 2022
Unique binary search trees II dynamic-programming	dynamic programming	O(n^2)	Sep 4, 2022
Unique binary search trees dynamic-programming	dynamic programming	O(n^2)	Sep 4, 2022
Verify preorder serialization of a binary tree stack	stack	O(n)	Sep 4, 2022
Vertical order traversal of a binary tree tree	tree	O(n)	Sep 4, 2022
Balance a binary search tree tree	tree	O(n)	Sep 3, 2022
Decode string stack	stack	O(n)	Sep 3, 2022
Design underground system design	design	O(1)	Sep 3, 2022
Equal row and column pairs array-and-hashmap	array and hashmap	O(n*m)	Sep 3, 2022
Gray code bit-manipulation	bit manipulation	O(2^n)	Sep 3, 2022
Largest number array-and-hashmap	array and hashmap	O(nlog(n))	Sep 3, 2022
Minimum moves to equal array elements II math-and-geometry	math and geometry	O(nlog(n))	Sep 3, 2022
Numbers with same consecutive differences backtracking	backtracking	O(n)	Sep 3, 2022
Sell diminishing valued colored balls heap	heap	O(nlog(n))	Sep 3, 2022
Average of levels in binary tree tree	tree	O(n)	Sep 2, 2022
Minimum time difference intervals	intervals	O(nlog(n))	Sep 2, 2022
Reachable nodes with restrictions graph	graph	O(ev)	Sep 2, 2022
Sudoku solver backtracking	backtracking	O(n^2)	Sep 2, 2022
Sum root to leaf numbers tree	tree	O(n)	Sep 2, 2022
4sum array-and-hashmap	array and hashmap	O(n^3)	Sep 1, 2022
Bitwise and of numbers range bit-manipulation	bit manipulation	O(n)	Sep 1, 2022
Clumsy factorial math-and-geometry	math and geometry	O(1)	Sep 1, 2022
Insertion sort list linked-list	linked list	O(n^2)	Sep 1, 2022
Integer to roman array-and-hashmap	array and hashmap	O(n)	Sep 1, 2022
Minimum height trees graph	graph	O(n)	Sep 1, 2022
Minimum moves to equal array elements math-and-geometry	math and geometry	O(n)	Sep 1, 2022
N-ary tree level order traversal tree	tree	O(n)	Sep 1, 2022
Next permutation array-and-hashmap	array and hashmap	O(n)	Sep 1, 2022
Simple bank system array-and-hashmap	array and hashmap	O(1)	Sep 1, 2022
Zigzag conversion array-and-hashmap	array and hashmap	O(n)	Sep 1, 2022
Continuous subarray sum array-and-hashmap	array and hashmap	O(n)	Aug 31, 2022
Rearrange words in a sentence array-and-hashmap	array and hashmap	O(nlog(n))	Aug 31, 2022
Subarray sum equals k array-and-hashmap	array and hashmap	O(n)	Aug 31, 2022
Furthest building you can reach heap	heap	O(nlog(l))	Aug 30, 2022
Get equal substrings within budget sliding-window	sliding window	O(n)	Aug 30, 2022
Maximum xor of two numbers in an array bit-manipulation	bit manipulation	O(n)	Aug 30, 2022
Minimum moves to make array complementary array-and-hashmap	array and hashmap	O(n+l)	Aug 30, 2022
Remove duplicates from sorted list II linked-list	linked list	O(n)	Aug 30, 2022
Remove duplicates from sorted list linked-list	linked list	O(n)	Aug 30, 2022
All paths from source to target backtracking	backtracking	O(2^n)	Aug 29, 2022
Divide two integers math-and-geometry	math and geometry	O(1)	Aug 29, 2022
Minimum size subarray sum sliding-window	sliding window	O(n)	Aug 29, 2022
Number of islands graph	graph	O(n^2)	Aug 29, 2022
Number of provinces graph	graph	O(n^2)	Aug 29, 2022
Remove duplicates from sorted array II array-and-hashmap	array and hashmap	O(nlog(n))	Aug 29, 2022
Remove duplicates from sorted array array-and-hashmap	array and hashmap	O(nlog(n))	Aug 29, 2022
Simplify path stack	stack	O(n)	Aug 29, 2022
Combinations backtracking	backtracking	O(nCk)	Aug 28, 2022
First missing positive array-and-hashmap	array and hashmap	O(n)	Aug 28, 2022
Game of life array-and-hashmap	array and hashmap	O(n*m)	Aug 28, 2022
Sort the matrix diagonally math-and-geometry	math and geometry	O(nmlog(n*m))	Aug 28, 2022
Unique paths II dynamic-programming	dynamic programming	O(n*m)	Aug 28, 2022
Validate stack sequences stack	stack	O(n)	Aug 28, 2022
3sum closest array-and-hashmap	array and hashmap	O(n^2)	Aug 27, 2022
Check if a string contains all binary codes of size k array-and-hashmap	array and hashmap	O(n*k)	Aug 27, 2022
Interval list intersections intervals	intervals	O(n+m)	Aug 27, 2022
Number of smooth descent periods of a stock dynamic-programming	dynamic programming	O(n)	Aug 27, 2022
Remove k digits stack	stack	O(n)	Aug 27, 2022
Swap nodes in pairs linked-list	linked list	O(n)	Aug 27, 2022
Minimum number of flips to make the binary string alternating greedy	greedy	O(n)	Aug 26, 2022
Reordered power of 2 bit-manipulation	bit manipulation	O(n^2)	Aug 26, 2022
Compare version numbers two-pointers	two pointers	O(n)	Aug 25, 2022
Count servers that communicate graph	graph	O(n*m)	Aug 25, 2022
Ransom note array-and-hashmap	array and hashmap	O(n+m)	Aug 25, 2022
Power of three math-and-geometry	math and geometry	O(log(n))	Aug 24, 2022
Rotate list linked-list	linked list	O(n)	Aug 24, 2022
Palindrome linked list linked-list	linked list	O(n)	Aug 23, 2022
Check if a word occurs as a prefix of any word in a sentence array-and-hashmap	array and hashmap	O(n)	Aug 22, 2022
Minimum deletions to make string balanced dynamic-programming	dynamic programming	O(n)	Aug 22, 2022
Power of four math-and-geometry	math and geometry	O(log(n))	Aug 22, 2022
Check if the sentence is pangram array-and-hashmap	array and hashmap	O(n)	Aug 21, 2022
Construct binary tree from preorder and postorder traversal tree	tree	O(n)	Aug 21, 2022
Cousins in binary tree tree	tree	O(n)	Aug 21, 2022
Number of good ways to split a string array-and-hashmap	array and hashmap	O(n)	Aug 21, 2022
Stamping the sequence greedy	greedy	O(n^2*m)	Aug 21, 2022
Minimum number of refueling stops heap	heap	O(n*log(n))	Aug 20, 2022
Number of pairs of strings with concatenation equal to target array-and-hashmap	array and hashmap	O(n)	Aug 20, 2022
The k weakest rows in a matrix heap	heap	O(nmlog(k))	Aug 20, 2022
Design parking system array-and-hashmap design	array and hashmap design	O(1)	Aug 19, 2022
Split array into consecutive subsequences array-and-hashmap	array and hashmap	O(n)	Aug 19, 2022
Reduce array size to the half array-and-hashmap	array and hashmap	O(n*log(n))	Aug 18, 2022
Strange printer dynamic-programming	dynamic programming	O(n^2)	Aug 18, 2022
Beautiful arrangement backtracking	backtracking	O(n^2)	Aug 17, 2022
Unique morse code words array-and-hashmap	array and hashmap	O(n*m)	Aug 17, 2022
Find triangular sum of an array math-and-geometry	math and geometry	O(n^2)	Aug 16, 2022
First unique character in a string array-and-hashmap	array and hashmap	O(n)	Aug 16, 2022
N-th tribonacci number dynamic-programming	dynamic programming	O(n)	Aug 16, 2022
String to integer atoi math-and-geometry	math and geometry	O(n)	Aug 16, 2022
Prime number of set bits in binary representation bit-manipulation	bit manipulation	O(n^2)	Aug 15, 2022
Roman to integer math-and-geometry	math and geometry	O(n)	Aug 15, 2022
Next greater element I stack	stack	O(n*m)	Aug 14, 2022
Word ladder II graph	graph	O((n+m)*l)	Aug 14, 2022
Design circular queue queue design	queue design	O(1)	Aug 13, 2022
Distinct subsequences dynamic-programming	dynamic programming	O(n*m)	Aug 13, 2022
Edit distance dynamic-programming	dynamic programming	O(n*m)	Aug 13, 2022
Regular expression matching dynamic-programming	dynamic programming	O(n*m)	Aug 13, 2022
Stream of characters trie	trie	O(n)	Aug 13, 2022
Substring with concatenation of all words sliding-window	sliding window	O(n*w)	Aug 13, 2022
Best time to buy and sell stock with cooldown dynamic-programming	dynamic programming	O(n)	Aug 12, 2022
Interleaving string dynamic-programming	dynamic programming	O(n*m)	Aug 12, 2022
Longest common subsequence dynamic-programming	dynamic programming	O(n*m)	Aug 12, 2022
Longest increasing path in a matrix dynamic-programming	dynamic programming	O(n*m)	Aug 12, 2022
Redundant connection graph	graph	O(n*log(n))	Aug 12, 2022
Walls and gates graph	graph	O(n*m)	Aug 12, 2022
Word ladder graph	graph	O(n^2)	Aug 12, 2022
Pacific atlantic water flow graph	graph	O(n*m)	Aug 11, 2022
Partition equal subset sum dynamic-programming	dynamic programming	O(sum(n))	Aug 11, 2022
Surrounded regions graph	graph	O(n*m)	Aug 11, 2022
Convert sorted array to binary search tree tree	tree	O(n)	Aug 10, 2022
Decode ways dynamic-programming	dynamic programming	O(n)	Aug 10, 2022
Maximum product subarray dynamic-programming	dynamic programming	O(n)	Aug 10, 2022
Partition labels greedy	greedy	O(n)	Aug 10, 2022
Word break dynamic-programming	dynamic programming	O(n)	Aug 10, 2022
Binary trees with factors dynamic-programming	dynamic programming	O(n^2)	Aug 9, 2022
Hand of straights greedy	greedy	O(n*log(n))	Aug 9, 2022
Longest palindromic substring dynamic-programming	dynamic programming	O(n)	Aug 9, 2022
Merge triplets to form target triplet greedy	greedy	O(n)	Aug 9, 2022
Valid parenthesis string greedy	greedy	O(n)	Aug 9, 2022
Clone graph graph	graph	O(n)	Aug 8, 2022
Gas station greedy	greedy	O(n)	Aug 8, 2022
House robber II dynamic-programming	dynamic programming	O(n)	Aug 8, 2022
Longest increasing subsequence dynamic-programming	dynamic programming	O(nlog(n))	Aug 8, 2022
Palindromic substrings dynamic-programming	dynamic programming	O(n)	Aug 8, 2022
Count vowels permutation dynamic-programming	dynamic programming	O(n)	Aug 7, 2022
Detect squares math-and-geometry	math and geometry	O(1)	Aug 7, 2022
Find median from data stream heap design	heap design	O(1)	Aug 7, 2022
Insert interval intervals	intervals	O(n)	Aug 7, 2022
Minimum interval to include each query intervals	intervals	O(n)	Aug 7, 2022
Multiply strings math-and-geometry	math and geometry	O(n*m)	Aug 7, 2022
Non overlapping intervals intervals	intervals	O(n)	Aug 7, 2022
Pow(x, n) math-and-geometry	math and geometry	O(log(n))	Aug 7, 2022
Rotate image math-and-geometry	math and geometry	O(n)	Aug 7, 2022
Set matrix zeroes math-and-geometry	math and geometry	O(n)	Aug 7, 2022
Spiral matrix math-and-geometry	math and geometry	O(n)	Aug 7, 2022
Binary tree maximum path sum tree	tree	O(n)	Aug 6, 2022
Design twitter heap design	heap design	O(1)	Aug 6, 2022
Kth smallest element in a bst tree	tree	O(n)	Aug 6, 2022
Letter combinations of a phone number backtracking	backtracking	O(n*n!)	Aug 6, 2022
Merge k sorted lists linked-list	linked list	O(n^2)	Aug 6, 2022
Poor pigs math-and-geometry	math and geometry	O(log(n))	Aug 6, 2022
Reverse nodes in k group linked-list	linked list	O(n)	Aug 6, 2022
Serialize and deserialize binary tree tree design	tree design	O(n)	Aug 6, 2022
Validate binary search tree tree	tree	O(n)	Aug 6, 2022
Coin change 2 dynamic-programming	dynamic programming	O(n*a)	Aug 5, 2022
Combination sum II backtracking	backtracking	O(2^n)	Aug 5, 2022
Combination sum IV dynamic-programming	dynamic programming	O(n*t)	Aug 5, 2022
Combination sum backtracking	backtracking	O(2^n)	Aug 5, 2022
LRU cache linked-list design	linked list design	O(1)	Aug 5, 2022
Find minimum in rotated sorted array binary-search	binary search	O(log(n))	Aug 4, 2022
Find the duplicate number linked-list	linked list	O(n)	Aug 4, 2022
Median of two sorted arrays binary-search	binary search	—	Aug 4, 2022
Mirror reflection math-and-geometry	math and geometry	O(n)	Aug 4, 2022
Search in rotated sorted array binary-search	binary search	O(log(n))	Aug 4, 2022
Minimum window substring sliding-window	sliding window	O(n)	Aug 3, 2022
My calendar I tree	tree	O(log(n))	Aug 3, 2022
Sliding window maximum sliding-window	sliding window	O(n)	Aug 3, 2022
Find eventual safe states graph	graph	O(n)	Aug 2, 2022
Kth smallest element in a sorted matrix heap	heap	O(mnlog(k))	Aug 2, 2022
Permutation in string sliding-window	sliding window	O(n)	Aug 2, 2022
Add two numbers linked-list	linked list	O(n)	Aug 1, 2022
Copy list with random pointer linked-list	linked list	O(n)	Aug 1, 2022
Koko eating bananas binary-search	binary search	—	Aug 1, 2022
Reorder list linked-list	linked list	O(n)	Aug 1, 2022
Climbing stairs dynamic-programming	dynamic programming	O(n)	Jul 31, 2022
Largest number at least twice of others array-and-hashmap	array and hashmap	O(n)	Jul 31, 2022
Min cost climbing stairs dynamic-programming	dynamic programming	O(n)	Jul 31, 2022
Perfect squares dynamic-programming	dynamic programming	O(n*a)	Jul 31, 2022
reverse-integer bit-manipulation	bit manipulation	O(1)	Jul 31, 2022
Sum of two integers math-and-geometry	math and geometry	O(1)	Jul 31, 2022
Car fleet stack	stack	O(n)	Jul 30, 2022
Daily temperatures stack	stack	O(n)	Jul 30, 2022
Largest rectangle in histogram stack	stack	O(n)	Jul 30, 2022
Top k frequent words heap	heap	O(n + k * log(n))	Jul 30, 2022
Word search II trie	trie	O(nm4^(n+k))	Jul 30, 2022
Word subsets array-and-hashmap	array and hashmap	O(n*m)	Jul 30, 2022
Find and replace pattern array-and-hashmap	array and hashmap	O(n)	Jul 29, 2022
Generate parentheses stack	stack	O(2^n)	Jul 29, 2022
Longest consecutive sequence array-and-hashmap	array and hashmap	O(n)	Jul 29, 2022
Longest repeating character replacement sliding-window	sliding window	O(n)	Jul 29, 2022
Search suggestions system array-and-hashmap	array and hashmap	O(n*m)	Jul 29, 2022
Happy number math-and-geometry	math and geometry	O(n)	Jul 28, 2022
Min cost to connect all points graph	graph	O(n^2 * log(n))	Jul 28, 2022
Palindrome partitioning backtracking	backtracking	O(2^n)	Jul 28, 2022
reconstruct-itinerary graph	graph	O(E^2)	Jul 28, 2022
Swim in rising water graph	graph	O(n^2 * log(n))	Jul 28, 2022
Flatten binary tree to linked list tree	tree	O(n)	Jul 27, 2022
Alien dictionary graph	graph	O(n)	Jul 26, 2022
Cheapest flights within k stops graph	graph	O(n*k)	Jul 26, 2022
Count good nodes in binary tree tree	tree	O(n)	Jul 26, 2022
Lowest common ancestor of a binary tree tree	tree	O(n)	Jul 26, 2022
Network delay time graph	graph	O(E*logV)	Jul 26, 2022
Verifying an alien dictionary graph	graph	O(n*k)	Jul 26, 2022
Brust balloons dynamic-programming	dynamic programming	O(n^3)	Jul 25, 2022
Find first and last position of element in sorted array binary-search	binary search	O(log(n))	Jul 25, 2022
Number of connected components in an undirected graph graph	graph	O(n*e)	Jul 25, 2022
Trapping rain water two-pointers	two pointers	O(n)	Jul 25, 2022
Implement queue using stacks queue design	queue design	O(1)	Jul 24, 2022
Longest substring without repeating characters sliding-window	sliding window	O(n)	Jul 24, 2022
Permutations II backtracking	backtracking	O(n^2)	Jul 24, 2022
Permutations backtracking	backtracking	O(n*n!)	Jul 24, 2022
Search a 2d matrix II binary-search	binary search	O(m*n)	Jul 24, 2022
Search a 2d matrix binary-search	binary search	O(log(n))	Jul 24, 2022
Subsets II backtracking	backtracking	O(2^n)	Jul 24, 2022
Word search backtracking	backtracking	O(nm4^n)	Jul 24, 2022
3Sum two-pointers	two pointers	O(n^2)	Jul 23, 2022
Design add and search words data structure trie design	trie design	O(n)	Jul 23, 2022
K closest points to origin heap	heap	O(nlog(n))	Jul 23, 2022
Kth largest element in an array heap	heap	O(n)	Jul 23, 2022
Last stone weight heap	heap	O(nlog(n))	Jul 23, 2022
Meeting rooms II intervals heap	intervals heap	O(nlog(n))	Jul 23, 2022
Plus one math-and-geometry	math and geometry	O(n)	Jul 23, 2022
Remove nth node from end of list linked-list	linked list	O(n)	Jul 23, 2022
Subsets backtracking	backtracking	O(2^n)	Jul 23, 2022
Task scheduler heap	heap	O(n)	Jul 23, 2022
Time based key value store binary-search design	binary search design	O(1)	Jul 23, 2022
Jump game II greedy	greedy	O(n)	Jul 22, 2022
Jump game greedy	greedy	O(n)	Jul 22, 2022
N-queens backtracking	backtracking	O(n^2)	Jul 22, 2022
Partition list linked-list	linked list	O(n)	Jul 22, 2022
Fibonacci number dynamic-programming	dynamic programming	O(n)	Jul 21, 2022
Graph valid tree graph	graph	O(n)	Jul 21, 2022
Implement stack using queues queue design	queue design	O(1)	Jul 21, 2022
Implement trie prefix tree trie design	trie design	O(n)	Jul 21, 2022
Maximum subarray greedy	greedy	O(n)	Jul 21, 2022
Meeting rooms intervals	intervals	O(nlog(n))	Jul 21, 2022
Merge intervals intervals	intervals	O(n)	Jul 21, 2022
Prime number of set bits in binary representation math-and-geometry	math and geometry	O(n)	Jul 21, 2022
Binary tree inorder traversal tree	tree	O(n)	Jul 20, 2022
Binary tree postorder traversal tree	tree	O(n)	Jul 20, 2022
Binary tree preorder traversal tree	tree	O(n)	Jul 20, 2022
Kth largest element in a stream heap	heap	O(1)	Jul 20, 2022
N-ary tree postorder traversal tree	tree	O(n)	Jul 20, 2022
N-ary tree preorder traversal tree	tree	O(n)	Jul 20, 2022
Binary search binary-search	binary search	O(log(n))	Jul 19, 2022
Evaluate reverse polish notation stack	stack	O(n)	Jul 19, 2022
Linked list cycle linked-list	linked list	O(n)	Jul 19, 2022
Min stack stack design	stack design	O(n+n)	Jul 19, 2022
Pascals triangle array-and-hashmap	array and hashmap	O(n)	Jul 19, 2022
Path sum tree	tree	O(n)	Jul 19, 2022
Encode and decode string array-and-hashmap	array and hashmap	O(n)	Jul 18, 2022
Find largest value in each tree row tree	tree	O(n)	Jul 18, 2022
Lowest common ancestor of a binary search tree tree	tree	O(n)	Jul 18, 2022
Minimum path sum dynamic-programming	dynamic programming	O(n*m)	Jul 18, 2022
Best time to buy and sell stock sliding-window	sliding window	O(n)	Jul 17, 2022
Coin change dynamic-programming	dynamic programming	O(n*a)	Jul 17, 2022
House robber dynamic-programming	dynamic programming	O(n)	Jul 17, 2022
Target sum dynamic-programming	dynamic programming	O(n*t)	Jul 17, 2022
Unique paths dynamic-programming	dynamic programming	O(n*m)	Jul 17, 2022
Number of 1 bits bit-manipulation	bit manipulation	O(n)	Jul 16, 2022
Course schedule II graph	graph	O(n+p)	Jul 16, 2022
Course schedule graph	graph	O(n+p)	Jul 16, 2022
Missing number bit-manipulation	bit manipulation	O(n)	Jul 16, 2022
Reverse bits bit-manipulation	bit manipulation	O(1)	Jul 16, 2022
Valid parentheses stack	stack	O(n)	Jul 16, 2022
Container with most water two-pointers	two pointers	O(n)	Jul 15, 2022
Merge two sorted list linked-list	linked list	O(n)	Jul 15, 2022
Reverse linked list linked-list	linked list	O(n)	Jul 15, 2022
Balanced binary tree tree	tree	O(n)	Jul 14, 2022
Construct binary tree from preorder and inorder traversal tree	tree	O(n)	Jul 14, 2022
Diameter of binary tree tree	tree	O(n)	Jul 14, 2022
Invert binary tree tree	tree	O(n)	Jul 14, 2022
Maximum depth of binary tree tree	tree	O(n)	Jul 14, 2022
Maximum depth of n-ary tree tree	tree	O(n)	Jul 14, 2022
Same tree tree	tree	O(n)	Jul 14, 2022
Subtree of another tree tree	tree	O(n^2)	Jul 14, 2022
Two sum II - input array is sorted two-pointers	two pointers	O(n)	Jul 14, 2022
Binary tree level order traversal tree	tree	—	Jul 13, 2022
Number of 1 bits bit-manipulation	bit manipulation	O(n)	Jul 13, 2022
Product of array except self array-and-hashmap	array and hashmap	O(n)	Jul 13, 2022
Single number bit-manipulation	bit manipulation	O(n)	Jul 13, 2022
Valid palindrome two-pointers	two pointers	O(n)	Jul 13, 2022
Valid sudoku array-and-hashmap	array and hashmap	O(n)	Jul 13, 2022
Group anagrams array-and-hashmap	array and hashmap	—	Jul 12, 2022
Rotting oranges graph	graph	O(n*m)	Jul 12, 2022
Top k frequent element array-and-hashmap	array and hashmap	O(n)	Jul 12, 2022
Valid anagram array-and-hashmap	array and hashmap	O(n)	Jul 12, 2022
Binary tree right side view tree	tree	O(n)	Jul 11, 2022
Max area of island graph	graph	O(n*m)	Jul 11, 2022
Contains duplicate array-and-hashmap	array and hashmap	O(n)	Jul 10, 2022
Two sum array-and-hashmap	array and hashmap	O(n)	Jul 10, 2022