These problems are related to array and hashmap.
Split strings by separator - July 24, 2023
Missing ranges - June 14, 2023
Check if all characters have equal number of occurrences - June 13, 2023
Summary ranges - June 11, 2023
Count negative numbers in a sorted matrix - June 7, 2023
Can make arithmetic progression from sequence - June 5, 2023
Left and right sum differences - May 24, 2023
Count vowel strings in ranges - May 24, 2023
Check if word equals summation of two words - May 19, 2023
Number of adjacent elements with the same color - May 18, 2023
Consecutive characters - May 14, 2023
Find permutation - May 12, 2023
Largest unique number - May 10, 2023
Prime in diagonal - May 8, 2023
Sort array by increasing frequency - May 7, 2023
Matrix diagonal sum - May 7, 2023
Concatenation of array - May 6, 2023
Maximum number of vowels in a substring of given length - May 5, 2023
Substrings that begin and end with the same letter - May 5, 2023
Index pairs of a string - May 4, 2023
Maximum sum with exactly k elements - May 4, 2023
Sentence similarity - February 1, 2023
Candy - January 21, 2023
Subarray sums divisible by k - January 19, 2023
Flip string to monotone increasing - January 17, 2023
Percentage of letter in string - January 16, 2023
Difference between element sum and digit sum of an array - January 15, 2023
Shuffle the array - January 10, 2023
Find good days to rob the bank - January 10, 2023
Find and replace in string - January 9, 2023
Confusing number - January 9, 2023
Minimum operations to make the array alternating - January 6, 2023
Number of segments in a string - January 5, 2023
Delete columns to make sorted - January 3, 2023
Car pooling - January 2, 2023
Sum of all odd length subarrays - January 1, 2023
adding-spaces-to-a-string - December 30, 2022
Remove letter to equalize frequency - December 30, 2022
3sum smaller - December 30, 2022
Minimum penalty for a shop - December 28, 2022
Design a leaderboard - December 28, 2022
Prefix and suffix search - December 27, 2022
Longest subsequence with limited sum - December 25, 2022
Most popular video creator - December 25, 2022
Reward top k students - December 25, 2022
Take k of each character from left and right - December 25, 2022
Custom sort string - December 24, 2022
Beautiful array - December 24, 2022
Count good meals - December 23, 2022
Ways to make a fair array - December 20, 2022
Shifting letters - December 20, 2022
Path crossing - December 19, 2022
Check if array pairs are divisible by k - December 19, 2022
Decode the message - December 19, 2022
Pancake sorting - December 18, 2022
Number of boomerangs - December 17, 2022
Maximum sum score of array - December 17, 2022
Replace elements in an array - December 17, 2022
Apply discount to prices - December 17, 2022
Encode number - December 16, 2022
Widest pair of indices with equal range sum - December 16, 2022
Count number of homogenous substrings - December 14, 2022
Minimum number of operations to move all balls to each box - December 14, 2022
Detect capital - December 13, 2022
Check whether two strings are almost equivalent - December 13, 2022
Average waiting time - December 12, 2022
Valid palindrome IV - December 10, 2022
Find the longest substring containing vowels in even counts - December 10, 2022
Longest substring with at least k repeating characters - December 9, 2022
Number of pairs of interchangeable rectangles - December 9, 2022
Can you eat your favorite candy on your favorite day - December 7, 2022
Maximum size subarray sum equals k - December 7, 2022
Number of subarrays having even product - December 7, 2022
Words within two edits of dictionary - December 7, 2022
Describe the painting - December 6, 2022
Alert using same key card three or more times in a one hour period - December 6, 2022
One edit distance - December 5, 2022
Wiggle sort - December 5, 2022
Minimum number of steps to make two strings anagram - December 4, 2022
Minimum number of steps to make two strings anagram II - December 4, 2022
Minimum average difference - December 4, 2022
Determine if two strings are close - December 2, 2022
Evaluate the bracket pairs of a string - December 1, 2022
Majority element II - December 1, 2022
Single row keyboard - December 1, 2022
Determine if string halves are alike - December 1, 2022
Fizz buzz - November 30, 2022
Unique number of occurrences - November 30, 2022
Unique word abbreviation - November 30, 2022
Find all lonely numbers in the array - November 30, 2022
Generate a string with characters that have odd counts - November 29, 2022
Reverse words in a string II - November 29, 2022
Find players with zero or one losses - November 28, 2022
Shortest word distance - November 28, 2022
Design hashset - November 28, 2022
Find smallest common element in all rows - November 26, 2022
Strobogrammatic number - November 26, 2022
The employee that worked on the longest task - November 24, 2022
Integer to english words - November 23, 2022
Sort colors - November 22, 2022
Random pick index - November 22, 2022
Vowel spellchecker - November 21, 2022
Sum of absolute differences in a sorted array - November 21, 2022
Maximum sum circular subarray - November 21, 2022
Reverse prefix of word - November 20, 2022
Widest vertical area between two points containing no points - November 20, 2022
Find all duplicates in an array - November 20, 2022
Number of ways to split array - November 19, 2022
Binary subarrays with sum - November 19, 2022
First letter to appear twice - November 18, 2022
Find the highest altitude - November 17, 2022
Finding the users active minutes - November 17, 2022
Minimum distance to the target element - November 16, 2022
Count days spent together - November 16, 2022
Making file names unique - November 16, 2022
Make two arrays equal by reversing subarrays - November 15, 2022
Merge strings alternately - November 14, 2022
Removing minimum number of magic beans - November 11, 2022
Distribute candies - November 9, 2022
Pascals triangle II - November 8, 2022
Maximum 69 number - November 7, 2022
Wiggle sort II - November 7, 2022
Jewels and stones - November 6, 2022
Orderly queue - November 6, 2022
Counting words with a given prefix - November 5, 2022
Majority element - November 5, 2022
Find all numbers disappeared in an array - November 5, 2022
Sum of beauty of all substrings - November 5, 2022
Word pattern - November 5, 2022
The k strongest values in an array - November 5, 2022
Find pivot index - November 5, 2022
Maximum number of balloons - November 5, 2022
Longest palindrome by concatenating two letter words - November 3, 2022
Count items matching a rule - November 2, 2022
Largest 3 same digit number in string - November 2, 2022
Where will the ball fall - November 1, 2022
Toeplitz matrix - October 31, 2022
Valid number - October 30, 2022
Divide array into equal pairs - October 30, 2022
Most frequent number following key in an array - October 29, 2022
Image overlap - October 27, 2022
Groups of special equivalent strings - October 26, 2022
Maximum number of pairs in array - October 26, 2022
Check if two string arrays are equivalent - October 25, 2022
Maximum length of a concatenated string with unique characters - October 24, 2022
Destination city - October 22, 2022
Unique email addresses - October 21, 2022
Isomorphic strings - October 21, 2022
Contains duplicate II - October 21, 2022
Queries on a permutation with key - October 19, 2022
Best sightseeing pair - October 17, 2022
Find numbers with even number of digits - October 16, 2022
Determine whether matrix can be obtained by rotation - October 12, 2022
Break a palindrome - October 10, 2022
Find all anagrams in a string - October 8, 2022
Remove element - October 8, 2022
Unique length 3 palindromic subsequences - October 8, 2022
Longest common prefix - October 6, 2022
Replace elements with greatest element on right side - October 6, 2022
Count nice pairs in an array - September 25, 2022
Reverse words in a string III - September 22, 2022
Sum of even numbers after queries - September 21, 2022
Find duplicate file in system - September 19, 2022
Validate ip address - September 15, 2022
Find original array from doubled array - September 15, 2022
Reorder data in log files - September 13, 2022
Sender with largest word count - September 12, 2022
Max sum of a pair with equal sum of digits - September 11, 2022
Partition array according to given pivot - September 10, 2022
Count and say - September 10, 2022
Tuple with same product - September 9, 2022
Sort characters by frequency - September 6, 2022
Reverse words in a string - September 6, 2022
H-index - September 6, 2022
H-index II - September 6, 2022
Sort an array - September 6, 2022
Largest number - September 3, 2022
Equal row and column pairs - September 3, 2022
4sum - September 1, 2022
Next permutation - September 1, 2022
Integer to roman - September 1, 2022
Zigzag conversion - September 1, 2022
Simple bank system - September 1, 2022
Rearrange words in a sentence - August 31, 2022
Subarray sum equals k - August 31, 2022
Continuous subarray sum - August 31, 2022
Minimum moves to make array complementary - August 30, 2022
Remove duplicates from sorted array - August 29, 2022
Remove duplicates from sorted array II - August 29, 2022
First missing positive - August 28, 2022
Game of life - August 28, 2022
Check if a string contains all binary codes of size k - August 27, 2022
3sum closest - August 27, 2022
Ransom note - August 25, 2022
Check if a word occurs as a prefix of any word in a sentence - August 22, 2022
Number of good ways to split a string - August 21, 2022
Check if the sentence is pangram - August 21, 2022
Number of pairs of strings with concatenation equal to target - August 20, 2022
Split array into consecutive subsequences - August 19, 2022
Design parking system - August 19, 2022
Reduce array size to the half - August 18, 2022
Unique morse code words - August 17, 2022
First unique character in a string - August 16, 2022
Largest number at least twice of others - July 31, 2022
Word subsets - July 30, 2022
Search suggestions system - July 29, 2022
Find and replace pattern - July 29, 2022
Longest consecutive sequence - July 29, 2022
Pascals triangle - July 19, 2022
Encode and decode string - July 18, 2022
Valid sudoku - July 13, 2022
Product of array except self - July 13, 2022
Group anagrams - July 12, 2022
Valid anagram - July 12, 2022
Top k frequent element - July 12, 2022
Contains duplicate - July 10, 2022
Two sum - July 10, 2022
