- Broken calculator
- Buddy strings
- Counting elements
- Decoded string at index
- Flip string to monotone increasing
- Leftmost column with at least a one
- Move pieces to obtain a string
- Range module
- Reordered power of 2
- Repeated dna sequences
- Repeated substring pattern
- Replace all digits with characters
- Replace elements in an array
- Reshape the matrix
- Reverse bits
- Reverse linked list
- Reverse linked list ii
- Reverse nodes in k group
- Reverse only letters
- Reverse pairs
- Reverse string
- Reverse words in a string
- Richest customer wealth
- Robot bounded in circle
- Roman to integer
- Rotate array
- Rotate image
- Rotate list
- Rotating the box
- Rotting oranges
- Running sum of 1d array
- Russian doll envelopes
- Same tree
- Score of parentheses
- Scramble string
- Search a 2d matrix
- Search a 2d matrix ii
- Search in a binary search tree
- Search in rotated sorted array
- Search in rotated sorted array ii
- Search insert position
- Search suggestions system
- Seat reservation manager
- Second largest digit in a string
- Selling pieces of wood
- Sentence similarity iii
- Sequential digits
- Serialize and deserialize binary tree
- Serialize and deserialize bst
- Set matrix zeroes
- Set mismatch
- Shift 2d grid
- Shifting letters
- Shifting letters ii
- Short encoding of words
- Shortest distance to a character
- Shortest impossible sequence of rolls
- Shortest palindrome
- Shortest path in a grid with obstacles elimination
- Shortest path in binary matrix
- Shortest path visiting all nodes
- Shortest subarray with sum at least k
- Shortest unsorted continuous subarray
- Shuffle an array
- Sign of the product of an array
- Simplify path
- Single element in a sorted array
- Single number
- Single number ii
- Single number iii
- Single threaded cpu
- Sliding puzzle
- Sliding window maximum
- Sliding window median
- Slowest key
- Smallest integer divisible by k
- Smallest number in infinite set
- Smallest range covering elements from k lists
- Smallest range ii
- Smallest string with a given numeric value
- Smallest string with swaps
- Smallest subtree with all the deepest nodes
- Snakes and ladders
- Sort array by increasing frequency
- Sort array by parity
- Sort array by parity ii
- Sort characters by frequency
- Sort colors
- Sort integers by the power value
- Sort items by groups respecting dependencies
- Sort list
- Sort the matrix diagonally
- Sorting the sentence
- Spiral matrix
- Spiral matrix ii
- Spiral matrix iv
- Split array into consecutive subsequences
- Split linked list in parts
- Splitting a string into descending consecutive values
- Sqrtx
- Squares of a sorted array
- Stamping the sequence
- Steps to make array non decreasing
- Stone game
- Stone game ii
- Stone game iv
- Stone game vii
- Stone game viii
- Stream of characters
- String compression
- String to integer atoi
- Strong password checker ii
- Subarray product less than k
- Subarray sum equals k
- Subarray with elements greater than varying threshold
- Subsets
- Subsets ii
- Substring with concatenation of all words
- Substrings of size three with distinct characters
- Subtree of another tree
- Successful pairs of spells and potions
- Sum of all subset xor totals
- Sum of beauty of all substrings
- Sum of digits in base k
- Sum of distances in tree
- Sum of floored pairs
- Sum of left leaves
- Sum of numbers with units digit k
- Sum of root to leaf binary numbers
- Sum of square numbers
- Sum root to leaf numbers
- Summary ranges
- Super palindromes
- Super washing machines
- Surrounded regions
- Swap nodes in pairs
- Swapping nodes in a linked list
- Swim in rising water
- Target sum
- Task scheduler
- Task scheduler ii
- Teemo attacking
- Tenth line
- Text justification
- The dining philosophers
- The earliest and latest rounds where players compete
- The k weakest rows in a matrix
- The kth factor of n
- The latest time to catch a bus
- The number of full rounds you have played
- The skyline problem
- Three equal parts
- Time based key value store
- Time needed to rearrange a binary string
- To lower case
- Top k frequent elements
- Top k frequent words
- Total appeal of a string
- Transform to chessboard
- Transpose matrix
- Trapping rain water
- Trapping rain water ii
- Triangle
- Trim a binary search tree
- Triples with bitwise and equal to zero
- Truncate sentence
- Two city scheduling
- Two sum
- Two sum ii input array is sorted
- Two sum iv input is a bst
- Ugly number ii
- Uncrossed lines
- Unique binary search trees
- Unique binary search trees ii
- Unique email addresses
- Unique morse code words
- Unique paths
- Unique paths ii
- Unique paths iii
- Valid anagram
- Valid mountain array
- Valid number
- Valid palindrome
- Valid palindrome ii
- Valid parentheses
- Valid parenthesis string
- Valid perfect square
- Valid square
- Valid sudoku
- Valid triangle number
- Validate binary search tree
- Validate ip address
- Validate stack sequences
- Verify preorder serialization of a binary tree
- Verifying an alien dictionary
- Vertical order traversal of a binary tree
- Vowel spellchecker
- Wiggle subsequence
- Wildcard matching
- Word break
- Word break ii
- Word ladder
- Word ladder ii
- Word pattern
- Word search
- Word subsets