Problem library

Array & Hashmap

All problems that are about array and hashmap.

217 / 217 problems

Problem	Category	Time	Solved
Split strings by separator array-and-hashmap	array and hashmap	O(n)	Jul 24, 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
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
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
Check if word equals summation of two words array-and-hashmap	array and hashmap	O(n)	May 19, 2023
Number of adjacent elements with the same color array-and-hashmap	array and hashmap	O(n)	May 18, 2023
Consecutive characters array-and-hashmap	array and hashmap	O(n)	May 14, 2023
Find permutation array-and-hashmap	array and hashmap	O(n)	May 12, 2023
Largest unique number array-and-hashmap	array and hashmap	O(n)	May 10, 2023
Prime in diagonal array-and-hashmap	array and hashmap	O(n)	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
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
Sentence similarity array-and-hashmap graph	array and hashmap graph	O(n)	Feb 1, 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
Flip string to monotone increasing array-and-hashmap	array and hashmap	O(n)	Jan 17, 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 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
Minimum operations to make the array alternating greedy array-and-hashmap	greedy array and hashmap	O(n)	Jan 6, 2023
Number of segments in a string array-and-hashmap	array and hashmap	O(n)	Jan 5, 2023
Delete columns to make sorted array-and-hashmap	array and hashmap	O(nm)	Jan 3, 2023
Car pooling array-and-hashmap	array and hashmap	O(nlogn)	Jan 2, 2023
Sum of all odd length subarrays array-and-hashmap	array and hashmap	O(n^3)	Jan 1, 2023
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
Design a leaderboard array-and-hashmap design	array and hashmap design	O(1)	Dec 28, 2022
Minimum penalty for a shop array-and-hashmap greedy	array and hashmap greedy	O(n)	Dec 28, 2022
Prefix and suffix search array-and-hashmap design	array and hashmap design	O(n)	Dec 27, 2022
Longest subsequence with limited sum array-and-hashmap	array and hashmap	O(nlog(n))	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
Count good meals array-and-hashmap	array and hashmap	O(nlog(n))	Dec 23, 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
Check if array pairs are divisible by k array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Decode the message array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Path crossing array-and-hashmap	array and hashmap	O(n)	Dec 19, 2022
Pancake sorting array-and-hashmap	array and hashmap	O(n^2)	Dec 18, 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
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
Encode number array-and-hashmap	array and hashmap	O(log(n))	Dec 16, 2022
Widest pair of indices with equal range sum array-and-hashmap	array and hashmap	O(n)	Dec 16, 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
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
Average waiting time intervals array-and-hashmap	intervals array and hashmap	O(n)	Dec 12, 2022
Find the longest substring containing vowels in even counts array-and-hashmap	array and hashmap	O(n)	Dec 10, 2022
Valid palindrome IV array-and-hashmap two-pointers	array and hashmap two pointers	O(n)	Dec 10, 2022
Longest substring with at least k repeating characters array-and-hashmap	array and hashmap	O(n)	Dec 9, 2022
Number of pairs of interchangeable rectangles array-and-hashmap	array and hashmap	O(n)	Dec 9, 2022
Can you eat your favorite candy on your favorite day array-and-hashmap	array and hashmap	O(n)	Dec 7, 2022
Maximum size subarray sum equals k array-and-hashmap	array and hashmap	O(n)	Dec 7, 2022
Number of subarrays having even product array-and-hashmap	array and hashmap	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
One edit distance array-and-hashmap	array and hashmap	O(n)	Dec 5, 2022
Wiggle sort array-and-hashmap	array and hashmap	O(n)	Dec 5, 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
Determine if two strings are close array-and-hashmap	array and hashmap	O(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
Majority element II array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Single row keyboard array-and-hashmap	array and hashmap	O(n)	Dec 1, 2022
Find all lonely numbers in the array array-and-hashmap	array and hashmap	O(n)	Nov 30, 2022
Fizz buzz array-and-hashmap	array and hashmap	O(n)	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
Generate a string with characters that have odd counts array-and-hashmap	array and hashmap	O(n)	Nov 29, 2022
Reverse words in a string II array-and-hashmap	array and hashmap	O(n)	Nov 29, 2022
Design hashset design array-and-hashmap	design array and hashmap	O(1)	Nov 28, 2022
Find players with zero or one losses array-and-hashmap	array and hashmap	O(nlog(n))	Nov 28, 2022
Shortest word distance array-and-hashmap	array and hashmap	O(n)	Nov 28, 2022
Find smallest common element in all rows array-and-hashmap	array and hashmap	O(n)	Nov 26, 2022
Strobogrammatic number array-and-hashmap	array and hashmap	O(n)	Nov 26, 2022
The employee that worked on the longest task array-and-hashmap	array and hashmap	O(n)	Nov 24, 2022
Integer to english words array-and-hashmap greedy	array and hashmap greedy	O(log(n))	Nov 23, 2022
Random pick index array-and-hashmap design	array and hashmap design	O(1)	Nov 22, 2022
Sort colors two-pointers array-and-hashmap	two pointers array and hashmap	O(n)	Nov 22, 2022
Maximum sum circular subarray array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
Sum of absolute differences in a sorted array array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
Vowel spellchecker array-and-hashmap	array and hashmap	O(n)	Nov 21, 2022
Find all duplicates in an array array-and-hashmap	array and hashmap	O(n)	Nov 20, 2022
Reverse prefix of word array-and-hashmap	array and hashmap	O(n)	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
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
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
Count days spent together array-and-hashmap	array and hashmap	O(1)	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
Make two arrays equal by reversing subarrays array-and-hashmap	array and hashmap	O(nlog(n))	Nov 15, 2022
Merge strings alternately array-and-hashmap	array and hashmap	O(n+m)	Nov 14, 2022
Removing minimum number of magic beans array-and-hashmap	array and hashmap	O(nlog(n))	Nov 11, 2022
Distribute candies array-and-hashmap	array and hashmap	O(n)	Nov 9, 2022
Pascals triangle II array-and-hashmap	array and hashmap	O(n)	Nov 8, 2022
Maximum 69 number array-and-hashmap	array and hashmap	O(n)	Nov 7, 2022
Wiggle sort II array-and-hashmap	array and hashmap	O(nlogn)	Nov 7, 2022
Jewels and stones array-and-hashmap	array and hashmap	O(n)	Nov 6, 2022
Orderly queue array-and-hashmap	array and hashmap	O(n^n)	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
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
Longest palindrome by concatenating two letter words array-and-hashmap	array and hashmap	O(n)	Nov 3, 2022
Count items matching a rule array-and-hashmap	array and hashmap	O(n)	Nov 2, 2022
Largest 3 same digit number in string array-and-hashmap	array and hashmap	O(n)	Nov 2, 2022
Where will the ball fall array-and-hashmap	array and hashmap	O(r*c)	Nov 1, 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
Valid number array-and-hashmap	array and hashmap	O(n)	Oct 30, 2022
Most frequent number following key in an array array-and-hashmap	array and hashmap	O(n)	Oct 29, 2022
Image overlap array-and-hashmap	array and hashmap	O(n^2)	Oct 27, 2022
Groups of special equivalent strings array-and-hashmap	array and hashmap	O(n*klog(k))	Oct 26, 2022
Maximum number of pairs in array array-and-hashmap	array and hashmap	O(n)	Oct 26, 2022
Check if two string arrays are equivalent array-and-hashmap	array and hashmap	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
Destination city array-and-hashmap	array and hashmap	O(n)	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
Queries on a permutation with key array-and-hashmap	array and hashmap	O(n^2)	Oct 19, 2022
Best sightseeing pair array-and-hashmap	array and hashmap	O(n)	Oct 17, 2022
Find numbers with even number of digits array-and-hashmap	array and hashmap	O(n^2)	Oct 16, 2022
Determine whether matrix can be obtained by rotation array-and-hashmap	array and hashmap	O(n^2)	Oct 12, 2022
Break a palindrome array-and-hashmap	array and hashmap	O(n)	Oct 10, 2022
Find all anagrams in a string array-and-hashmap	array and hashmap	O(n*m)	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
Longest common prefix array-and-hashmap	array and hashmap	O(n^m)	Oct 6, 2022
Replace elements with greatest element on right side array-and-hashmap	array and hashmap	O(n)	Oct 6, 2022
Count nice pairs in an array array-and-hashmap	array and hashmap	O(n)	Sep 25, 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
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
Reorder data in log files array-and-hashmap	array and hashmap	O(nlog(n))	Sep 13, 2022
Sender with largest word count array-and-hashmap	array and hashmap	O(nlog(n))	Sep 12, 2022
Max sum of a pair with equal sum of digits array-and-hashmap	array and hashmap	O(n)	Sep 11, 2022
Count and say array-and-hashmap	array and hashmap	O(n)	Sep 10, 2022
Partition array according to given pivot array-and-hashmap	array and hashmap	O(n)	Sep 10, 2022
Tuple with same product array-and-hashmap	array and hashmap	O(n^2)	Sep 9, 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
Reverse words in a string array-and-hashmap	array and hashmap	O(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
Equal row and column pairs array-and-hashmap	array and hashmap	O(n*m)	Sep 3, 2022
Largest number array-and-hashmap	array and hashmap	O(nlog(n))	Sep 3, 2022
4sum array-and-hashmap	array and hashmap	O(n^3)	Sep 1, 2022
Integer to roman array-and-hashmap	array and hashmap	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
Minimum moves to make array complementary array-and-hashmap	array and hashmap	O(n+l)	Aug 30, 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
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
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
Ransom note array-and-hashmap	array and hashmap	O(n+m)	Aug 25, 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
Check if the sentence is pangram array-and-hashmap	array and hashmap	O(n)	Aug 21, 2022
Number of good ways to split a string array-and-hashmap	array and hashmap	O(n)	Aug 21, 2022
Number of pairs of strings with concatenation equal to target array-and-hashmap	array and hashmap	O(n)	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
Unique morse code words array-and-hashmap	array and hashmap	O(n*m)	Aug 17, 2022
First unique character in a string array-and-hashmap	array and hashmap	O(n)	Aug 16, 2022
Largest number at least twice of others array-and-hashmap	array and hashmap	O(n)	Jul 31, 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
Longest consecutive sequence array-and-hashmap	array and hashmap	O(n)	Jul 29, 2022
Search suggestions system array-and-hashmap	array and hashmap	O(n*m)	Jul 29, 2022
Pascals triangle array-and-hashmap	array and hashmap	O(n)	Jul 19, 2022
Encode and decode string array-and-hashmap	array and hashmap	O(n)	Jul 18, 2022
Product of array except self array-and-hashmap	array and hashmap	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
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
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