All problems

Every problem in the bank, grouped by its primary pattern.

0 / 189 done · 189 shown

Arrays & Hashing

Analyze User Website Visit Pattern↻Medium
Contains Duplicate↻Easy
Encode and Decode Strings↻Medium
Group Anagrams↻Medium
Insert Delete GetRandom O(1)↻Medium
Invalid Transactions↻Medium
Longest Consecutive Sequence↻Medium
Majority Element↻Easy
Maximum Product of Three Numbers↻Easy
Product of Array Except Self↻Medium
Rotate Array↻Medium
Snapshot Array↻Medium
Subarray Sum Equals K↻Medium
Top K Frequent Elements↻Medium
Two Sum↻Easy
Valid Anagram↻Easy
Valid Sudoku↻Medium

Two Pointers

3Sum↻Medium
Container With Most Water↻Medium
Merge Sorted Array↻Easy
Move Zeroes↻Easy
Remove Duplicates from Sorted Array↻Easy
Reverse Words in a String↻Medium
Trapping Rain Water↻Hard
Two Sum II Input Array Is Sorted↻Medium
Valid Palindrome↻Easy

Sliding Window

Best Time to Buy and Sell Stock↻Easy
Design Hit Counter↻Medium
Find the Index of the First Occurrence in a String↻Easy
Fruit Into Baskets↻Medium
Longest Repeating Character Replacement↻Medium
Longest Substring Without Repeating Characters↻Medium
Maximum Average Subarray I↻Easy
Maximum Coins From K Consecutive Bags↻Medium
Minimum Window Substring↻Hard
Permutation In String↻Medium
Sliding Window Maximum↻Hard
Subarray Product Less Than K↻Medium

Stack

Binary Search

Binary Search↻Easy
Find First and Last Position of Element in Sorted Array↻Medium
Find Minimum In Rotated Sorted Array↻Medium
Koko Eating Bananas↻Medium
Median of Two Sorted Arrays↻Hard
Search a 2D Matrix↻Medium
Search In Rotated Sorted Array↻Medium
Single Element in a Sorted Array↻Medium
Split Array Largest Sum↻Hard
Time Based Key Value Store↻Medium

Linked List

Trees

Amount of Time for Binary Tree to Be Infected↻Medium
Balanced Binary Tree↻Easy
Binary Tree Level Order Traversal↻Medium
Binary Tree Maximum Path Sum↻Hard
Binary Tree Right Side View↻Medium
Construct Binary Tree From Preorder And Inorder Traversal↻Medium
Count Good Nodes In Binary Tree↻Medium
Diameter of Binary Tree↻Easy
House Robber III↻Medium
Invert Binary Tree↻Easy
Kth Smallest Element In a Bst↻Medium
Lowest Common Ancestor of a Binary Search Tree↻Medium
Lowest Common Ancestor of a Binary Tree↻Medium
Maximum Depth of Binary Tree↻Easy
Same Tree↻Easy
Serialize And Deserialize Binary Tree↻Hard
Subtree of Another Tree↻Easy
Validate Binary Search Tree↻Medium

Tries

Design Add And Search Words Data Structure↻Medium
Implement Trie Prefix Tree↻Medium
Word Search II↻Hard

Heap / Priority Queue

Backtracking

Combination Sum↻Medium
Combination Sum II↻Medium
Generate Parentheses↻Medium
Letter Combinations of a Phone Number↻Medium
N Queens↻Hard
Palindrome Partitioning↻Medium
Permutations↻Medium
Subsets↻Medium
Subsets II↻Medium
Word Search↻Medium

Graphs

Clone Graph↻Medium
Course Schedule↻Medium
Course Schedule II↻Medium
Graph Valid Tree↻Medium
Max Area of Island↻Medium
Number of Connected Components In An Undirected Graph↻Medium
Number of Islands↻Medium
Pacific Atlantic Water Flow↻Medium
Redundant Connection↻Medium
Rotting Oranges↻Medium
Surrounded Regions↻Medium
Walls And Gates↻Medium
Word Ladder↻Hard

Advanced Graphs

1-D DP

2-D DP

Best Time to Buy And Sell Stock With Cooldown↻Medium
Burst Balloons↻Hard
Coin Change II↻Medium
Distinct Subsequences↻Hard
Edit Distance↻Medium
Interleaving String↻Medium
Longest Common Subsequence↻Medium
Longest Increasing Path In a Matrix↻Hard
Predict the Winner↻Medium
Regular Expression Matching↻Hard
Target Sum↻Medium
Unique Paths↻Medium

Greedy

Best Time to Buy and Sell Stock II↻Medium
Best Time to Buy and Sell Stock with Transaction Fee↻Medium
Gas Station↻Medium
Hand of Straights↻Medium
Jump Game↻Medium
Jump Game II↻Medium
Maximum Subarray↻Medium
Merge Triplets to Form Target Triplet↻Medium
Minimum Operations to Make Array Non-Decreasing↻Medium
Partition Labels↻Medium
Valid Parenthesis String↻Medium

Intervals

Insert Interval↻Medium
Meeting Rooms↻Easy
Meeting Rooms II↻Medium
Merge Intervals↻Medium
Minimum Interval to Include Each Query↻Hard
Non Overlapping Intervals↻Medium

Math & Geometry

Strings

Bit Manipulation

Counting Bits↻Easy
Missing Number↻Easy
Number of 1 Bits↻Easy
Partition Array Into Two Arrays to Minimize Sum Difference↻Hard
Reverse Bits↻Easy
Reverse Integer↻Medium
Single Number↻Easy
Sum of Two Integers↻Medium