Problems

Blind 75 list of problems

Reverse Bits

Editorial
url-leetcode-reverse-bits (URL)
Bit ManipulationDivide and Conquer
1

Word Break

Editorial
url-leetcode-word-break (URL)
Dynamic ProgrammingArrayTrieMemoizationHash TableString
1

Group Anagrams

Editorial
url-leetcode-group-anagrams (URL)
SortingArrayHash TableString
1

Word Search II

Editorial
url-leetcode-word-search-ii (URL)
TrieDepth First SearchDesignString
1

Merge Intervals

Editorial
url-leetcode-merge-intervals (URL)
SortingArray
1

Non-overlapping Intervals

Editorial
url-leetcode-non-overlapping-intervals (URL)
ArrayGreedySortingDynamic Programming
1

Maximum Depth of Binary Tree

Editorial
url-leetcode-maximum-depth-of-binary-tree (URL)
Breadth First SearchDepth First SearchBinary TreeTree
1

Search in Rotated Sorted Array

Editorial
url-leetcode-search-in-rotated-sorted-array (URL)
ArrayBinary Search
1

Construct Binary Tree from Preorder and Inorder Traversal

Editorial
url-leetcode-construct-binary-tree-from-preorder-and-inorder-traversal (URL)
Binary TreeArrayDivide and ConquerHash TableTree
1

Product of Array Except Self

Editorial
url-leetcode-product-of-array-except-self (URL)
Prefix SumArray
1

House Robber

Editorial
url-leetcode-house-robber (URL)
ArrayDynamic Programming
1

Reorder List

Editorial
url-leetcode-reorder-list (URL)
Linked ListRecursionStackTwo Pointers
1

Valid Palindrome

Editorial
url-leetcode-valid-palindrome (URL)
Two PointersString
1

Insert Interval

Editorial
url-leetcode-insert-interval (URL)
Array
1

Two Sum

Editorial
url-leetcode-two-sum (URL)
Hash TableArray
1

Jump Game

Editorial
url-leetcode-jump-game (URL)
ArrayGreedyDynamic Programming
1

Same Tree

Editorial
url-leetcode-same-tree (URL)
Breadth First SearchDepth First SearchBinary TreeTree
1

Decode Ways

Editorial
url-leetcode-decode-ways (URL)
Dynamic ProgrammingString
1

Container With Most Water

Editorial
url-leetcode-container-with-most-water (URL)
ArrayTwo PointersGreedy
1

Climbing Stairs

Editorial
url-leetcode-climbing-stairs (URL)
MemoizationDynamic ProgrammingMath
1

Reverse Linked List

Editorial
url-leetcode-reverse-linked-list (URL)
RecursionLinked List
1

Coin Change

Editorial
url-leetcode-coin-change (URL)
ArrayBreadth First SearchDynamic Programming
1

Number of 1 Bits

Editorial
url-leetcode-number-of-1-bits (URL)
Divide and ConquerBit Manipulation
1

Linked List Cycle

Editorial
url-leetcode-linked-list-cycle (URL)
Hash TableTwo PointersLinked List
1

Longest Common Subsequence

Editorial
url-leetcode-longest-common-subsequence (URL)
Dynamic ProgrammingString
2

Longest Palindromic Substring

Editorial
url-leetcode-longest-palindromic-substring (URL)
StringTwo PointersDynamic Programming
1

Combination Sum IV

Editorial
url-leetcode-combination-sum-iv (URL)
ArrayDynamic Programming
1

House Robber II

Editorial
url-leetcode-house-robber-ii (URL)
Dynamic ProgrammingArray
1

Implement Trie (Prefix Tree)

Editorial
url-leetcode-implement-trie-prefix-tree (URL)
TrieHash TableDesignString
1

Design Add and Search Words Data Structure

Editorial
url-leetcode-design-add-and-search-words-data-structure (URL)
StringDesignDepth First SearchTrie
1

Meeting Rooms II

Editorial
url-neetcode-meeting-schedule-ii (URL)
SortingPrefix SumHeap Priority QueueArrayTwo PointersGreedy
1

Valid Anagram

Editorial
url-leetcode-valid-anagram (URL)
SortingHash TableString
1

Lowest Common Ancestor of a Binary Search Tree

Editorial
url-leetcode-lowest-common-ancestor-of-a-binary-search-tree (URL)
TreeBinary Search TreeDepth First SearchBinary Tree
1

Maximum Subarray

Editorial
url-leetcode-maximum-subarray (URL)
Dynamic ProgrammingArrayDivide and Conquer
1

Longest Repeating Character Replacement

Editorial
url-leetcode-longest-repeating-character-replacement (URL)
StringHash TableSliding Window
1

Clone Graph

Editorial
url-leetcode-clone-graph (URL)
Hash TableGraphDepth First SearchBreadth First Search
1

Word Search

Editorial
url-leetcode-word-search (URL)
Depth First SearchArrayMatrixBacktrackingString
1

Contains Duplicate

Editorial
url-leetcode-contains-duplicate (URL)
Hash TableArraySorting
1

Best Time to Buy and Sell Stock

Editorial
url-leetcode-best-time-to-buy-and-sell-stock (URL)
ArrayDynamic Programming
1

Merge Two Sorted Lists

Editorial
url-leetcode-merge-two-sorted-lists (URL)
Linked ListRecursion
1

Palindromic Substrings

Editorial
url-leetcode-palindromic-substrings (URL)
Dynamic ProgrammingTwo PointersString
1

Binary Tree Level Order Traversal

Editorial
url-leetcode-binary-tree-level-order-traversal (URL)
Binary TreeBreadth First SearchTree
1

Set Matrix Zeroes

Editorial
url-leetcode-set-matrix-zeroes (URL)
ArrayMatrixHash Table
1

Longest Substring Without Repeating Characters

Editorial
url-leetcode-longest-substring-without-repeating-characters (URL)
Sliding WindowHash TableString
1

Rotate Image

Editorial
url-leetcode-rotate-image (URL)
MathArrayMatrix
1

Serialize and Deserialize Binary Tree

Editorial
url-leetcode-serialize-and-deserialize-binary-tree (URL)
Binary TreeDepth First SearchBreadth First SearchDesignStringTree
1

Remove Nth Node From End of List

Editorial
url-leetcode-remove-nth-node-from-end-of-list (URL)
Two PointersLinked List
1

3Sum

Editorial
url-leetcode-3sum (URL)
Two PointersArraySorting
1

Graph Valid Tree

Editorial
url-neetcode-valid-tree (URL)
GraphUnion FindBreadth First SearchDepth First Search
1

Number of Islands

Editorial
url-leetcode-number-of-islands (URL)
ArrayUnion FindMatrixBreadth First SearchDepth First Search
1

Longest Consecutive Sequence

Editorial
url-leetcode-longest-consecutive-sequence (URL)
Hash TableUnion FindArray
1

Unique Paths

Editorial
url-leetcode-unique-paths (URL)
Dynamic ProgrammingCombinatoricsMath
2

Subtree of Another Tree

Editorial
url-leetcode-subtree-of-another-tree (URL)
TreeHash FunctionString MatchingBinary TreeDepth First Search
1

Merge k Sorted Lists

Editorial
url-leetcode-merge-k-sorted-lists (URL)
Linked ListMerge SortDivide and ConquerHeap Priority Queue
1

Find Minimum in Rotated Sorted Array

Editorial
url-leetcode-find-minimum-in-rotated-sorted-array (URL)
ArrayBinary Search
1

Number of Connected Components in an Undirected Graph

Editorial
url-neetcode-count-connected-components (URL)
Union FindGraphBreadth First SearchDepth First Search
1

Binary Tree Maximum Path Sum

Editorial
url-leetcode-binary-tree-maximum-path-sum (URL)
TreeDepth First SearchDynamic ProgrammingBinary Tree
1

Spiral Matrix

Editorial
url-leetcode-spiral-matrix (URL)
SimulationArrayMatrix
1

Alien Dictionary

Editorial
url-neetcode-foreign-dictionary (URL)
Topological SortBreadth First SearchDepth First SearchStringGraphArray
1

Minimum Window Substring

Editorial
url-leetcode-minimum-window-substring (URL)
Sliding WindowStringHash Table
1

Course Schedule

Editorial
url-leetcode-course-schedule (URL)
Depth First SearchBreadth First SearchTopological SortGraph
1

Invert Binary Tree

Editorial
url-leetcode-invert-binary-tree (URL)
Binary TreeBreadth First SearchDepth First SearchTree
1

Kth Smallest Element in a BST

Editorial
url-leetcode-kth-smallest-element-in-a-bst (URL)
TreeBinary Search TreeDepth First SearchBinary Tree
1

Top K Frequent Elements

Editorial
url-leetcode-top-k-frequent-elements (URL)
Bucket SortHash TableQuickselectDivide and ConquerArrayHeap Priority QueueCountingSorting
1

Validate Binary Search Tree

Editorial
url-leetcode-validate-binary-search-tree (URL)
Depth First SearchBinary TreeTreeBinary Search Tree
1

Encode and Decode Strings

Editorial
url-neetcode-string-encode-and-decode (URL)
ArrayString
1

Counting Bits

Editorial
url-leetcode-counting-bits (URL)
Bit ManipulationDynamic Programming
1

Meeting Rooms

Editorial
url-neetcode-meeting-schedule (URL)
SortingArray
1

Sum of Two Integers

Editorial
url-leetcode-sum-of-two-integers (URL)
Bit ManipulationMath
1

Longest Increasing Subsequence

Editorial
url-leetcode-longest-increasing-subsequence (URL)
Dynamic ProgrammingBinary SearchArray
1

Valid Parentheses

Editorial
url-leetcode-valid-parentheses (URL)
StackString
1

Pacific Atlantic Water Flow

Editorial
url-leetcode-pacific-atlantic-water-flow (URL)
Depth First SearchBreadth First SearchArrayMatrix
1

Maximum Product Subarray

Editorial
url-leetcode-maximum-product-subarray (URL)
ArrayDynamic Programming
1