CS Journal

Big O Cheat Sheet
Cornell
Cornell
- AML
  AML
- MLE
  MLE
  - MLE
Interviews
Interviews
- Apple
Leetcode
Leetcode
- DFS
  DFS
  - 1372. Longest ZigZag Path in a Binary Tree
- Data Structure
  Data Structure
  - LinkedList
- Dynamic Programming (DP)
  Dynamic Programming (DP)
- Easy
  Easy
  - 1822. Sign of the Product of an Array
- Others
  Others
- Code
  Code
  - Python Codes
  - 1 two sum
    1 two sum
    
    Index
    
    Two sum
  - 10 regular expression matching
    10 regular expression matching
    
    Index
    
    Regular expression matching
  - 100 same tree
    100 same tree
    
    Index
    
    Same tree
  - 101 symmetric tree
    101 symmetric tree
    
    Index
    
    Symmetric tree
  - 1013 fibonacci number
    1013 fibonacci number
    
    Index
    
    Fibonacci number
  - 1014 k closest points to origin
    1014 k closest points to origin
    
    Index
    
    K closest points to origin
  - 1019 squares of a sorted array
    1019 squares of a sorted array
    
    Index
    
    Squares of a sorted array
  - 102 binary tree level order traversal
    102 binary tree level order traversal
    
    Index
    
    Binary tree level order traversal
  - 1036 rotting oranges
    1036 rotting oranges
    
    Index
    
    Rotting oranges
  - 1039 find the town judge
    1039 find the town judge
    
    Index
  - 104 maximum depth of binary tree
    104 maximum depth of binary tree
    
    Index
    
    Maximum depth of binary tree
  - 1046 max consecutive ones iii
    1046 max consecutive ones iii
    
    Index
    
    Max consecutive ones iii
  - 105 construct binary tree from preorder and inorder traversal
    105 construct binary tree from preorder and inorder traversal
    
    Index
    
    Construct binary tree from preorder and inorder traversal
  - 1055 pairs of songs with total durations divisible by 60
    1055 pairs of songs with total durations divisible by 60
    
    Index
    
    Pairs of songs with total durations divisible by 60
  - 1056 capacity to ship packages within d days
    1056 capacity to ship packages within d days
    
    Index
    
    Capacity to ship packages within d days
  - 106 construct binary tree from inorder and postorder traversal
    106 construct binary tree from inorder and postorder traversal
    
    Index
    
    Construct binary tree from inorder and postorder traversal
  - 1073 number of enclaves
    1073 number of enclaves
    
    Index
    
    Number of enclaves
  - 108 convert sorted array to binary search tree
    108 convert sorted array to binary search tree
    
    Index
    
    Convert sorted array to binary search tree
  - 11 container with most water
    11 container with most water
    
    Index
    
    Container with most water
  - 110 balanced binary tree
    110 balanced binary tree
    
    Index
    
    Balanced binary tree
  - 111 minimum depth of binary tree
    111 minimum depth of binary tree
    
    Index
    
    Minimum depth of binary tree
  - 1112 find words that can be formed by characters
    1112 find words that can be formed by characters
    
    Index
    
    Find words that can be formed by characters
  - 1116 maximum level sum of a binary tree
    1116 maximum level sum of a binary tree
    
    Index
    
    Maximum level sum of a binary tree
  - 1119 robot bounded in circle
    1119 robot bounded in circle
    
    Index
  - 112 path sum
    112 path sum
    
    Index
    
    Path sum
  - 1127 last stone weight
    1127 last stone weight
    
    Index
    
    Last stone weight
  - 1128 remove all adjacent duplicates in string
    1128 remove all adjacent duplicates in string
    
    Index
    
    Remove all adjacent duplicates in string
  - 1130 last stone weight ii
    1130 last stone weight ii
    
    Index
    
    Last stone weight ii
  - 1137 height checker
    1137 height checker
    
    Index
    
    Height checker
  - 114 flatten binary tree to linked list
    114 flatten binary tree to linked list
    
    Index
    
    Flatten binary tree to linked list
  - 1146 greatest common divisor of strings
    1146 greatest common divisor of strings
    
    Index
    
    Greatest common divisor of strings
  - 115 distinct subsequences
    115 distinct subsequences
    
    Index
    
    Distinct subsequences
  - 116 populating next right pointers in each node
    116 populating next right pointers in each node
    
    Index
    
    Populating next right pointers in each node
  - 117 populating next right pointers in each node ii
    117 populating next right pointers in each node ii
    
    Index
    
    Populating next right pointers in each node ii
  - 1184 car pooling
    1184 car pooling
    
    Index
    
    Car pooling
  - 1200 remove interval
    1200 remove interval
    
    Index
    
    Remove interval
  - 1205 defanging an ip address
    1205 defanging an ip address
    
    Index
    
    Defanging an ip address
  - 121 best time to buy and sell stock
    121 best time to buy and sell stock
    
    Index
    
    Best time to buy and sell stock
  - 122 best time to buy and sell stock ii
    122 best time to buy and sell stock ii
    
    Index
    
    Best time to buy and sell stock ii
  - 123 best time to buy and sell stock iii
    123 best time to buy and sell stock iii
    
    Index
    
    Best time to buy and sell stock iii
  - 1236 n th tribonacci number
    1236 n th tribonacci number
    
    Index
    
    N th tribonacci number
  - 124 binary tree maximum path sum
    124 binary tree maximum path sum
    
    Index
    
    Binary tree maximum path sum
  - 125 valid palindrome
    125 valid palindrome
    
    Index
    
    Valid palindrome
  - 127 word ladder
    127 word ladder
    
    Index
    
    Word ladder
  - 13 roman to integer
    13 roman to integer
    
    Index
    
    Roman to integer
  - 130 surrounded regions
    130 surrounded regions
    
    Index
    
    Surrounded regions
  - 1304 longest happy string
    1304 longest happy string
    
    Index
    
    Longest happy string
  - 131 palindrome partitioning
    131 palindrome partitioning
    
    Index
    
    Palindrome partitioning
  - 1319 unique number of occurrences
    1319 unique number of occurrences
    
    Index
    
    Unique number of occurrences
  - 1320 remove all adjacent duplicates in string ii
    1320 remove all adjacent duplicates in string ii
    
    Index
    
    Remove all adjacent duplicates in string ii
  - 133 clone graph
    133 clone graph
    
    Index
    
    Clone graph
  - 134 gas station
    134 gas station
    
    Index
    
    Gas station
  - 136 single number
    136 single number
    
    Index
    
    Single number
  - 1375 find palindrome with fixed length
    1375 find palindrome with fixed length
    
    Index
    
    Find palindrome with fixed length
  - 139 word break
    139 word break
    
    Index
    
    Word break
  - 141 linked list cycle
    141 linked list cycle
    
    Index
    
    Linked list cycle
  - 1414 shortest path in a grid with obstacles elimination
    1414 shortest path in a grid with obstacles elimination
    
    Index
    
    Shortest path in a grid with obstacles elimination
  - 142 linked list cycle ii
    142 linked list cycle ii
    
    Index
    
    Linked list cycle ii
  - 144 binary tree preorder traversal
    144 binary tree preorder traversal
    
    Index
    
    Binary tree preorder traversal
  - 1445 number of sub arrays of size k and average greater than or equal to threshold
    1445 number of sub arrays of size k and average greater than or equal to threshold
    
    Index
    
    Number of sub arrays of size k and average greater than or equal to threshold
  - 1447 jump game iv
    1447 jump game iv
    
    Index
    
    Jump game iv
  - 146 lru cache
    146 lru cache
    
    Index
    
    Lru cache
  - 1464 reduce array size to the half
    1464 reduce array size to the half
    
    Index
    
    Reduce array size to the half
  - 1482 how many numbers are smaller than the current number
    1482 how many numbers are smaller than the current number
    
    Index
    
    How many numbers are smaller than the current number
  - 15 3sum
    15 3sum
    
    Index
    
    3sum
  - 150 evaluate reverse polish notation
    150 evaluate reverse polish notation
    
    Index
    
    Evaluate reverse polish notation
  - 151 reverse words in a string
    151 reverse words in a string
    
    Index
    
    Reverse words in a string
  - 152 maximum product subarray
    152 maximum product subarray
    
    Index
    
    Maximum product subarray
  - 1528 kids with the greatest number of candies
    1528 kids with the greatest number of candies
    
    Index
    
    Kids with the greatest number of candies
  - 153 find minimum in rotated sorted array
    153 find minimum in rotated sorted array
    
    Index
    
    Find minimum in rotated sorted array
  - 1539 diagonal traverse ii
    1539 diagonal traverse ii
    
    Index
    
    Diagonal traverse ii
  - 155 min stack
    155 min stack
    
    Index
    
    Min stack
  - 1567 maximum number of vowels in a substring of given length
    1567 maximum number of vowels in a substring of given length
    
    Index
    
    Maximum number of vowels in a substring of given length
  - 1576 reorder routes to make all paths lead to the city zero
    1576 reorder routes to make all paths lead to the city zero
    
    Index
  - 1585 the kth factor of n
    1585 the kth factor of n
    
    Index
    
    The kth factor of n
  - 1586 longest subarray of 1s after deleting one element
    1586 longest subarray of 1s after deleting one element
    
    Index
    
    Longest subarray of 1s after deleting one element
  - 160 intersection of two linked lists
    160 intersection of two linked lists
    
    Index
    
    Intersection of two linked lists
  - 1604 least number of unique integers after k removals
    1604 least number of unique integers after k removals
    
    Index
    
    Least number of unique integers after k removals
  - 163 missing ranges
    163 missing ranges
    
    Index
    
    Missing ranges
  - 1635 number of good pairs
    1635 number of good pairs
    
    Index
    
    Number of good pairs
  - 1648 minimum insertions to balance a parentheses string
    1648 minimum insertions to balance a parentheses string
    
    Index
    
    Minimum insertions to balance a parentheses string
  - 167 two sum ii input array is sorted
    167 two sum ii input array is sorted
    
    Index
    
    Two sum ii input array is sorted
  - 1678 number of ways to split a string
    1678 number of ways to split a string
    
    Index
    
    Number of ways to split a string
  - 169 majority element
    169 majority element
    
    Index
    
    Majority element
  - 17 letter combinations of a phone number
    17 letter combinations of a phone number
    
    Index
    
    Letter combinations of a phone number
  - 1713 dot product of two sparse vectors
    1713 dot product of two sparse vectors
    
    Index
    
    Dot product of two sparse vectors
  - 173 binary search tree iterator
    173 binary search tree iterator
    
    Index
    
    Binary search tree iterator
  - 1730 special array with x elements greater than or equal x
    1730 special array with x elements greater than or equal x
    
    Index
    
    Special array with x elements greater than or equal x
  - 1752 arithmetic subarrays
    1752 arithmetic subarrays
    
    Index
    
    Arithmetic subarrays
  - 1770 minimum deletions to make character frequencies unique
    1770 minimum deletions to make character frequencies unique
    
    Index
    
    Minimum deletions to make character frequencies unique
  - 1777 determine if two strings are close
    1777 determine if two strings are close
    
    Index
    
    Determine if two strings are close
  - 1798 max number of k sum pairs
    1798 max number of k sum pairs
    
    Index
    
    Max number of k sum pairs
  - 18 4sum
    18 4sum
    
    Index
    
    4sum
  - 1833 find the highest altitude
    1833 find the highest altitude
    
    Index
    
    Find the highest altitude
  - 188 best time to buy and sell stock iv
    188 best time to buy and sell stock iv
    
    Index
    
    Best time to buy and sell stock iv
  - 1885 count number of homogenous substrings
    1885 count number of homogenous substrings
    
    Index
    
    Count number of homogenous substrings
  - 1894 merge strings alternately
    1894 merge strings alternately
    
    Index
    
    Merge strings alternately
  - 1899 count items matching a rule
    1899 count items matching a rule
    
    Index
    
    Count items matching a rule
  - 19 remove nth node from end of list
    19 remove nth node from end of list
    
    Index
    
    Remove nth node from end of list
  - 1908 recyclable and low fat products
    1908 recyclable and low fat products
    
    Index
  - 1925 count nice pairs in an array
    1925 count nice pairs in an array
    
    Index
    
    Count nice pairs in an array
  - 1966 frequency of the most frequent element
    1966 frequency of the most frequent element
    
    Index
    
    Frequency of the most frequent element
  - 198 house robber
    198 house robber
    
    Index
    
    Notes
    
    House robber
  - 1988 minimize maximum pair sum in array
    1988 minimize maximum pair sum in array
    
    Index
    
    Minimize maximum pair sum in array
  - 199 binary tree right side view
    199 binary tree right side view
    
    Index
    
    Binary tree right side view
  - 2 add two numbers
    2 add two numbers
    
    Index
  - 20 valid parentheses
    20 valid parentheses
    
    Index
    
    Valid parentheses
  - 200 number of islands
    200 number of islands
    
    Index
    
    Number of islands
  - 202 happy number
    202 happy number
    
    Index
    
    Happy number
  - 2026 merge triplets to form target triplet
    2026 merge triplets to form target triplet
    
    Index
    
    Merge triplets to form target triplet
  - 203 remove linked list elements
    203 remove linked list elements
    
    Index
    
    Remove linked list elements
  - 2038 nearest exit from entrance in maze
    2038 nearest exit from entrance in maze
    
    Index
    
    Nearest exit from entrance in maze
  - 206 reverse linked list
    206 reverse linked list
    
    Index
    
    Reverse linked list
  - 207 course schedule
    207 course schedule
    
    Index
    
    Course schedule
  - 208 implement trie prefix tree
    208 implement trie prefix tree
    
    Index
    
    Implement trie prefix tree
  - 209 minimum size subarray sum
    209 minimum size subarray sum
    
    Index
    
    Minimum size subarray sum
  - 21 merge two sorted lists
    21 merge two sorted lists
    
    Index
    
    Merge two sorted lists
  - 210 course schedule ii
    210 course schedule ii
    
    Index
    
    Course schedule ii
  - 2107 find unique binary string
    2107 find unique binary string
    
    Index
    
    Find unique binary string
  - 211 design add and search words data structure
    211 design add and search words data structure
    
    Index
    
    Design add and search words data structure
  - 2121 find if path exists in graph
    2121 find if path exists in graph
    
    Index
    
    Find if path exists in graph
  - 213 house robber ii
    213 house robber ii
    
    Index
    
    House robber ii
  - 2149 remove colored pieces if both neighbors are the same color
    2149 remove colored pieces if both neighbors are the same color
    
    Index
    
    Remove colored pieces if both neighbors are the same color
  - 215 kth largest element in an array
    215 kth largest element in an array
    
    Index
    
    Kth largest element in an array
  - 216 combination sum iii
    216 combination sum iii
    
    Index
    
    Combination sum iii
  - 217 contains duplicate
    217 contains duplicate
    
    Index
  - 22 generate parentheses
    22 generate parentheses
    
    Index
    
    Generate parentheses
  - 2216 delete the middle node of a linked list
    2216 delete the middle node of a linked list
    
    Index
    
    Delete the middle node of a linked list
  - 2219 maximum number of words found in sentences
    2219 maximum number of words found in sentences
    
    Index
    
    Maximum number of words found in sentences
  - 2220 find all possible recipes from given supplies
    2220 find all possible recipes from given supplies
    
    Index
    
    Find all possible recipes from given supplies
  - 2236 maximum twin sum of a linked list
    2236 maximum twin sum of a linked list
    
    Index
    
    Maximum twin sum of a linked list
  - 225 implement stack using queues
    225 implement stack using queues
    
    Index
    
    Implement stack using queues
  - 226 invert binary tree
    226 invert binary tree
    
    Index
    
    Invert binary tree
  - 2269 count elements with strictly smaller and greater elements
    2269 count elements with strictly smaller and greater elements
    
    Index
    
    Count elements with strictly smaller and greater elements
  - 2271 rearrange array elements by sign
    2271 rearrange array elements by sign
    
    Index
    
    Rearrange array elements by sign
  - 229 majority element ii
    229 majority element ii
    
    Index
    
    Majority element ii
  - 23 merge k sorted lists
    23 merge k sorted lists
    
    Index
    
    Merge k sorted lists
  - 230 kth smallest element in a bst
    230 kth smallest element in a bst
    
    Index
    
    Kth smallest element in a bst
  - 231 power of two
    231 power of two
    
    Index
    
    Power of two
  - 232 implement queue using stacks
    232 implement queue using stacks
    
    Index
    
    Implement queue using stacks
  - 234 palindrome linked list
    234 palindrome linked list
    
    Index
    
    Palindrome linked list
  - 235 lowest common ancestor of a binary search tree
    235 lowest common ancestor of a binary search tree
    
    Index
    
    Lowest common ancestor of a binary search tree
  - 236 lowest common ancestor of a binary tree
    236 lowest common ancestor of a binary tree
    
    Index
    
    Lowest common ancestor of a binary tree
  - 2361 calculate digit sum of a string
    2361 calculate digit sum of a string
    
    Index
    
    Calculate digit sum of a string
  - 238 product of array except self
    238 product of array except self
    
    Index
    
    Product of array except self
  - 2383 add two integers
    2383 add two integers
    
    Index
    
    Add two integers
  - 239 sliding window maximum
    239 sliding window maximum
    
    Index
    
    Sliding window maximum
  - 2392 successful pairs of spells and potions
    2392 successful pairs of spells and potions
    
    Index
    
    Successful pairs of spells and potions
  - 24 swap nodes in pairs
    24 swap nodes in pairs
    
    Index
  - 240 search a 2d matrix ii
    240 search a 2d matrix ii
    
    Index
    
    Search a 2d matrix ii
  - 2413 smallest number in infinite set
    2413 smallest number in infinite set
    
    Index
    
    Smallest number in infinite set
  - 242 valid anagram
    242 valid anagram
    
    Index
    
    Valid anagram
  - 2428 equal row and column pairs
    2428 equal row and column pairs
    
    Index
    
    Equal row and column pairs
  - 2470 removing stars from a string
    2470 removing stars from a string
    
    Index
    
    Removing stars from a string
  - 2471 minimum amount of time to collect garbage
    2471 minimum amount of time to collect garbage
    
    Index
    
    Minimum amount of time to collect garbage
  - 2491 smallest even multiple
    2491 smallest even multiple
    
    Index
    
    Smallest even multiple
  - 2502 sort the people
    2502 sort the people
    
    Index
    
    Sort the people
  - 252 meeting rooms
    252 meeting rooms
    
    Index
    
    Meeting rooms
  - 253 meeting rooms ii
    253 meeting rooms ii
    
    Index
    
    Meeting rooms ii
  - 2563 split message based on limit
    2563 split message based on limit
    
    Index
    
    Split message based on limit
  - 2565 merge operations to turn array into a palindrome
    2565 merge operations to turn array into a palindrome
    
    Index
    
    Merge operations to turn array into a palindrome
  - 257 binary tree paths
    257 binary tree paths
    
    Index
    
    Binary tree paths
  - 259 3sum smaller
    259 3sum smaller
    
    Index
    
    3sum smaller
  - 261 graph valid tree
    261 graph valid tree
    
    Index
    
    Graph valid tree
  - 2620 find consecutive integers from a data stream
    2620 find consecutive integers from a data stream
    
    Index
    
    Find consecutive integers from a data stream
  - 268 missing number
    268 missing number
    
    Index
    
    Missing number
  - 27 remove element
    27 remove element
    
    Index
    
    Remove element
  - 2747 apply transform over each element in array
    2747 apply transform over each element in array
    
    Index
  - 276 paint fence
    276 paint fence
    
    Index
    
    Paint fence
  - 2767 maximum sum with exactly k elements
    2767 maximum sum with exactly k elements
    
    Index
    
    Maximum sum with exactly k elements
  - 279 perfect squares
    279 perfect squares
    
    Index
    
    Perfect squares
  - 28 find the index of the first occurrence in a string
    28 find the index of the first occurrence in a string
    
    Index
    
    Find the index of the first occurrence in a string
  - 283 move zeroes
    283 move zeroes
    
    Index
    
    Move zeroes
  - 2845 find the value of the partition
    2845 find the value of the partition
    
    Index
    
    Find the value of the partition
  - 286 walls and gates
    286 walls and gates
    
    Index
    
    Walls and gates
  - 287 find the duplicate number
    287 find the duplicate number
    
    Index
    
    Find the duplicate number
  - 293 flip game
    293 flip game
    
    Index
    
    Flip game
  - 295 find median from data stream
    295 find median from data stream
    
    Index
    
    Find median from data stream
  - 2953 count pairs of points with distance k
    2953 count pairs of points with distance k
    
    Index
    
    Count pairs of points with distance k
  - 3 longest substring without repeating characters
    3 longest substring without repeating characters
    
    Index
    
    Longest substring without repeating characters
  - 300 longest increasing subsequence
    300 longest increasing subsequence
    
    Index
    
    Longest increasing subsequence
  - 3080 split array into maximum number of subarrays
    3080 split array into maximum number of subarrays
    
    Index
    
    Split array into maximum number of subarrays
  - 3081 minimum array length after pair removals
    3081 minimum array length after pair removals
    
    Index
    
    Minimum array length after pair removals
  - 309 best time to buy and sell stock with cooldown
    309 best time to buy and sell stock with cooldown
    
    Index
    
    Best time to buy and sell stock with cooldown
  - 3094 minimum number of operations to make array empty
    3094 minimum number of operations to make array empty
    
    Index
    
    Minimum number of operations to make array empty
  - 312 burst balloons
    312 burst balloons
    
    Index
    
    Burst balloons
  - 316 remove duplicate letters
    316 remove duplicate letters
    
    Index
    
    Remove duplicate letters
  - 322 coin change
    322 coin change
    
    Index
    
    Coin change
  - 323 number of connected components in an undirected graph
    323 number of connected components in an undirected graph
    
    Index
    
    Number of connected components in an undirected graph
  - 3262 find polygon with the largest perimeter
    3262 find polygon with the largest perimeter
    
    Index
    
    Find polygon with the largest perimeter
  - 328 odd even linked list
    328 odd even linked list
    
    Index
    
    Odd even linked list
  - 329 longest increasing path in a matrix
    329 longest increasing path in a matrix
    
    Index
    
    Longest increasing path in a matrix
  - 33 search in rotated sorted array
    33 search in rotated sorted array
    
    Index
    
    Search in rotated sorted array
  - 332 reconstruct itinerary
    332 reconstruct itinerary
    
    Index
  - 334 increasing triplet subsequence
    334 increasing triplet subsequence
    
    Index
    
    Increasing triplet subsequence
  - 337 house robber iii
    337 house robber iii
    
    Index
    
    House robber iii
  - 34 find first and last position of element in sorted array
    34 find first and last position of element in sorted array
    
    Index
    
    Find first and last position of element in sorted array
  - 343 integer break
    343 integer break
    
    Index
    
    Integer break
  - 344 reverse string
    344 reverse string
    
    Index
    
    Reverse string
  - 345 reverse vowels of a string
    345 reverse vowels of a string
    
    Index
    
    Reverse vowels of a string
  - 346 moving average from data stream
    346 moving average from data stream
    
    Index
    
    Moving average from data stream
  - 347 top k frequent elements
    347 top k frequent elements
    
    Index
    
    Top k frequent elements
  - 349 intersection of two arrays
    349 intersection of two arrays
    
    Index
    
    Intersection of two arrays
  - 355 design twitter
    355 design twitter
    
    Index
    
    Design twitter
  - 368 largest divisible subset
    368 largest divisible subset
    
    Index
    
    Largest divisible subset
  - 37 sudoku solver
    37 sudoku solver
    
    Index
    
    Sudoku solver
  - 374 guess number higher or lower
    374 guess number higher or lower
    
    Index
    
    Guess number higher or lower
  - 376 wiggle subsequence
    376 wiggle subsequence
    
    Index
    
    Wiggle subsequence
  - 377 combination sum iv
    377 combination sum iv
    
    Index
    
    Combination sum iv
  - 383 ransom note
    383 ransom note
    
    Index
    
    Ransom note
  - 387 first unique character in a string
    387 first unique character in a string
    
    Index
    
    First unique character in a string
  - 39 combination sum
    39 combination sum
    
    Index
    
    Combination sum
  - 392 is subsequence
    392 is subsequence
    
    Index
    
    Is subsequence
  - 394 decode string
    394 decode string
    
    Index
    
    Decode string
  - 399 evaluate division
    399 evaluate division
    
    Index
    
    Evaluate division
  - 4 median of two sorted arrays
    4 median of two sorted arrays
    
    Index
    
    Median of two sorted arrays
  - 40 combination sum ii
    40 combination sum ii
    
    Index
    
    Combination sum ii
  - 402 remove k digits
    402 remove k digits
    
    Index
    
    Remove k digits
  - 404 sum of left leaves
    404 sum of left leaves
    
    Index
    
    Sum of left leaves
  - 416 partition equal subset sum
    416 partition equal subset sum
    
    Index
    
    Partition equal subset sum
  - 417 pacific atlantic water flow
    417 pacific atlantic water flow
    
    Index
    
    Pacific atlantic water flow
  - 418 sentence screen fitting
    418 sentence screen fitting
    
    Index
    
    Sentence screen fitting
  - 42 trapping rain water
    42 trapping rain water
    
    Index
    
    Trapping rain water
  - 435 non overlapping intervals
    435 non overlapping intervals
    
    Index
    
    Non overlapping intervals
  - 44 wildcard matching
    44 wildcard matching
    
    Index
    
    Wildcard matching
  - 443 string compression
    443 string compression
    
    Index
  - 45 jump game ii
    45 jump game ii
    
    Index
    
    Jump game ii
  - 450 delete node in a bst
    450 delete node in a bst
    
    Index
    
    Delete node in a bst
  - 454 4sum ii
    454 4sum ii
    
    Index
    
    4sum ii
  - 455 assign cookies
    455 assign cookies
    
    Index
    
    Assign cookies
  - 459 repeated substring pattern
    459 repeated substring pattern
    
    Index
    
    Repeated substring pattern
  - 46 permutations
    46 permutations
    
    Index
    
    Permutations
  - 463 island perimeter
    463 island perimeter
    
    Index
    
    Island perimeter
  - 465 optimal account balancing
    465 optimal account balancing
    
    Index
    
    Optimal account balancing
  - 47 permutations ii
    47 permutations ii
    
    Index
    
    Permutations ii
  - 474 ones and zeroes
    474 ones and zeroes
    
    Index
    
    Ones and zeroes
  - 48 rotate image
    48 rotate image
    
    Index
    
    Rotate image
  - 49 group anagrams
    49 group anagrams
    
    Index
    
    Group anagrams
  - 491 non decreasing subsequences
    491 non decreasing subsequences
    
    Index
    
    Non decreasing subsequences
  - 494 target sum
    494 target sum
    
    Index
    
    Target sum
  - 5 longest palindromic substring
    5 longest palindromic substring
    
    Index
    
    Longest palindromic substring
  - 501 find mode in binary search tree
    501 find mode in binary search tree
    
    Index
    
    Find mode in binary search tree
  - 509 inorder successor in bst ii
    509 inorder successor in bst ii
    
    Index
    
    Inorder successor in bst ii
  - 51 n queens
    51 n queens
    
    Index
    
    N queens
  - 513 find bottom left tree value
    513 find bottom left tree value
    
    Index
    
    Find bottom left tree value
  - 515 find largest value in each tree row
    515 find largest value in each tree row
    
    Index
    
    Find largest value in each tree row
  - 518 coin change ii
    518 coin change ii
    
    Index
    
    Coin change ii
  - 52 n queens ii
    52 n queens ii
    
    Index
    
    N queens ii
  - 521 longest uncommon subsequence i
    521 longest uncommon subsequence i
    
    Index
    
    Longest uncommon subsequence i
  - 53 maximum subarray
    53 maximum subarray
    
    Index
    
    Maximum subarray
  - 530 minimum absolute difference in bst
    530 minimum absolute difference in bst
    
    Index
    
    Minimum absolute difference in bst
  - 538 convert bst to greater tree
    538 convert bst to greater tree
    
    Index
    
    Convert bst to greater tree
  - 541 reverse string ii
    541 reverse string ii
    
    Index
    
    Reverse string ii
  - 542 01 matrix
    542 01 matrix
    
    Index
    
    01 matrix
  - 543 diameter of binary tree
    543 diameter of binary tree
    
    Index
    
    Diameter of binary tree
  - 547 number of provinces
    547 number of provinces
    
    Index
    
    Number of provinces
  - 55 jump game
    55 jump game
    
    Index
    
    Jump game
  - 557 reverse words in a string iii
    557 reverse words in a string iii
    
    Index
    
    Reverse words in a string iii
  - 56 merge intervals
    56 merge intervals
    
    Index
    
    Merge intervals
  - 567 permutation in string
    567 permutation in string
    
    Index
    
    Permutation in string
  - 57 insert interval
    57 insert interval
    
    Index
    
    Insert interval
  - 572 subtree of another tree
    572 subtree of another tree
    
    Index
    
    Subtree of another tree
  - 588 design in memory file system
    588 design in memory file system
    
    Index
    
    Design in memory file system
  - 59 spiral matrix ii
    59 spiral matrix ii
    
    Index
    
    Spiral matrix ii
  - 605 can place flowers
    605 can place flowers
    
    Index
    
    Can place flowers
  - 617 merge two binary trees
    617 merge two binary trees
    
    Index
    
    Merge two binary trees
  - 62 unique paths
    62 unique paths
    
    Index
    
    Unique paths
  - 621 task scheduler
    621 task scheduler
    
    Index
    
    Task scheduler
  - 63 unique paths ii
    63 unique paths ii
    
    Index
    
    Unique paths ii
  - 637 average of levels in binary tree
    637 average of levels in binary tree
    
    Index
    
    Average of levels in binary tree
  - 643 maximum average subarray i
    643 maximum average subarray i
    
    Index
    
    Maximum average subarray i
  - 647 palindromic substrings
    647 palindromic substrings
    
    Index
    
    Palindromic substrings
  - 654 maximum binary tree
    654 maximum binary tree
    
    Index
    
    Maximum binary tree
  - 666 path sum iv
    666 path sum iv
    
    Index
    
    Path sum iv
  - 669 trim a binary search tree
    669 trim a binary search tree
    
    Index
    
    Trim a binary search tree
  - 674 longest continuous increasing subsequence
    674 longest continuous increasing subsequence
    
    Index
    
    Longest continuous increasing subsequence
  - 678 valid parenthesis string
    678 valid parenthesis string
    
    Index
    
    Valid parenthesis string
  - 68 text justification
    68 text justification
    
    Index
    
    Text justification
  - 684 redundant connection
    684 redundant connection
    
    Index
    
    Redundant connection
  - 694 number of distinct islands
    694 number of distinct islands
    
    Index
    
    Number of distinct islands
  - 695 max area of island
    695 max area of island
    
    Index
    
    Max area of island
  - 7 reverse integer
    7 reverse integer
    
    Index
    
    Reverse integer
  - 70 climbing stairs
    70 climbing stairs
    
    Index
    
    Climbing stairs
  - 714 best time to buy and sell stock with transaction fee
    714 best time to buy and sell stock with transaction fee
    
    Index
    
    Best time to buy and sell stock with transaction fee
  - 718 maximum length of repeated subarray
    718 maximum length of repeated subarray
    
    Index
    
    Maximum length of repeated subarray
  - 72 edit distance
    72 edit distance
    
    Index
    
    Edit distance
  - 724 find pivot index
    724 find pivot index
    
    Index
    
    Find pivot index
  - 735 asteroid collision
    735 asteroid collision
    
    Index
  - 739 daily temperatures
    739 daily temperatures
    
    Index
    
    Daily temperatures
  - 747 min cost climbing stairs
    747 min cost climbing stairs
    
    Index
    
    Min cost climbing stairs
  - 764 n ary tree level order traversal
    764 n ary tree level order traversal
    
    Index
    
    N ary tree level order traversal
  - 768 partition labels
    768 partition labels
    
    Index
    
    Partition labels
  - 77 combinations
    77 combinations
    
    Index
    
    Combinations
  - 78 subsets
    78 subsets
    
    Index
    
    Subsets
  - 783 search in a binary search tree
    783 search in a binary search tree
    
    Index
    
    Search in a binary search tree
  - 784 insert into a binary search tree
    784 insert into a binary search tree
    
    Index
    
    Insert into a binary search tree
  - 785 basic calculator iii
    785 basic calculator iii
    
    Index
    
    Basic calculator iii
  - 79 word search
    79 word search
    
    Index
    
    Word search
  - 792 binary search
    792 binary search
    
    Index
    
    Binary search
  - 813 all paths from source to target
    813 all paths from source to target
    
    Index
    
    All paths from source to target
  - 815 champagne tower
    815 champagne tower
    
    Index
    
    Champagne tower
  - 816 design hashset
    816 design hashset
    
    Index
    
    Design hashset
  - 817 design hashmap
    817 design hashmap
    
    Index
    
    Design hashmap
  - 833 bus routes
    833 bus routes
    
    Index
    
    Bus routes
  - 838 design linked list
    838 design linked list
    
    Index
  - 84 largest rectangle in histogram
    84 largest rectangle in histogram
    
    Index
    
    Largest rectangle in histogram
  - 86 partition list
    86 partition list
    
    Index
    
    Partition list
  - 871 keys and rooms
    871 keys and rooms
    
    Index
    
    Keys and rooms
  - 876 hand of straights
    876 hand of straights
    
    Index
    
    Hand of straights
  - 88 merge sorted array
    88 merge sorted array
    
    Index
    
    Merge sorted array
  - 886 score of parentheses
    886 score of parentheses
    
    Index
    
    Score of parentheses
  - 90 subsets ii
    90 subsets ii
    
    Index
    
    Subsets ii
  - 904 leaf similar trees
    904 leaf similar trees
    
    Index
    
    Leaf similar trees
  - 908 middle of the linked list
    908 middle of the linked list
    
    Index
    
    Middle of the linked list
  - 91 decode ways
    91 decode ways
    
    Index
    
    Decode ways
  - 916 decoded string at index
    916 decoded string at index
    
    Index
    
    Decoded string at index
  - 92 reverse linked list ii
    92 reverse linked list ii
    
    Index
    
    Reverse linked list ii
  - 93 restore ip addresses
    93 restore ip addresses
    
    Index
    
    Restore ip addresses
  - 932 monotonic array
    932 monotonic array
    
    Index
    
    Monotonic array
  - 948 sort an array
    948 sort an array
    
    Index
    
    Sort an array
  - 96 unique binary search trees
    96 unique binary search trees
    
    Index
    
    Unique binary search trees
  - 962 flip string to monotone increasing
    962 flip string to monotone increasing
    
    Index
    
    Flip string to monotone increasing
  - 967 minimum falling path sum
    967 minimum falling path sum
    
    Index
    
    Minimum falling path sum
  - 969 number of recent calls
    969 number of recent calls
    
    Index
    
    Number of recent calls
  - 97 interleaving string
    97 interleaving string
    
    Index
    
    Interleaving string
  - 98 validate binary search tree
    98 validate binary search tree
    
    Index
    
    Validate binary search tree
  - 982 minimum increment to make array unique
    982 minimum increment to make array unique
    
    Index
    
    Minimum increment to make array unique
  - Best time to buy and sell stock
    Best time to buy and sell stock
    
    Index
  - Climbing stairs
    Climbing stairs
    
    Index
  - Length of last word
    Length of last word
    
    Index
  - Longest repeating character replacement
    Longest repeating character replacement
    
    Index
    
    Longest repeating character replacement
  - Longest substring without repeating characters
    Longest substring without repeating characters
    
    Index
  - Median of two sorted arrays
    Median of two sorted arrays
    
    Index
  - Merge two sorted lists
    Merge two sorted lists
    
    Index
    
    Merge two sorted lists
  - Minimum depth of binary tree
    Minimum depth of binary tree
    
    Index
    
    Minimum depth of binary tree
  - Minimum window substring
    Minimum window substring
    
    Index
    
    Minimum window substring
  - Optimal partition of string
    Optimal partition of string
    
    Index
    
    Optimal partition of string
  - Permutation in string
    Permutation in string
    
    Index
    
    Permutation in string
  - Remove duplicates from sorted list
    Remove duplicates from sorted list
    
    Index
  - Remove element
    Remove element
    
    Index
  - Remove nth node from end of list
    Remove nth node from end of list
    
    Index
    
    Remove nth node from end of list
  - Reorder list
    Reorder list
    
    Index
    
    Reorder list
  - Search in rotated sorted array
    Search in rotated sorted array
    
    Index
  - The kth factor of n
    The kth factor of n
    
    Index
    
    The kth factor of n
  - Time based key value store
    Time based key value store
    
    Index
  - Two sum
    Two sum
    
    Index
    
    Two sum
Others
Others
Problems
Problems

Python Codes