Problem Explorer

Problem	Categories	Java	Scala	Python	C++
Balanced Binary Tree Easy	Tree Depth-First Search Binary Tree			—	—
Binary Search Easy	Array Binary Search
Binary Tree Level Order Traversal Medium	Tree Breadth-First Search Binary Tree		—	—	—
Binary Tree Right Side View Medium	Tree Depth-First Search Breadth-First Search Binary Tree		—	—	—
Binary Tree Zigzag Level Order Traversal Medium	Tree Breadth-First Search Binary Tree		—	—	—
Burst Balloons Hard	Array Dynamic Programming		—	—	—
Coin Change Medium	Array Dynamic Programming Breadth-First Search		—	—	—
Coin Change II Medium	Array Dynamic Programming		—	—	—
Combination Sum Medium	Array Backtracking		—	—	—
Construct Binary Tree from Preorder and Inorder Traversal Medium	Array Hash Table Divide and Conquer Tree Binary Tree		—	—	—
Container With Most Water Medium	Array Two Pointers Greedy	—		—	—
Course Schedule Medium	Depth-First Search Breadth-First Search Graph Theory Topological Sort		—	—	—
Decode Ways Medium	String Dynamic Programming		—	—	—
Delete Operation for Two Strings Medium	String Dynamic Programming		—	—	—
Edit Distance Medium	String Dynamic Programming		—	—	—
Find All Anagrams in a String Medium	Hash Table String Sliding Window	—		—	—
Find First and Last Position of Element in Sorted Array Medium	Array Binary Search		—	—
Find if Path Exists in Graph Easy	Depth-First Search Breadth-First Search Union-Find Graph Theory		—	—	—
Find Median from Data Stream Hard	Two Pointers Design Sorting Heap (Priority Queue) Data Stream		—	—	—
Find Minimum in Rotated Sorted Array Medium	Array Binary Search		—	—
Find Minimum Time to Finish All Jobs Hard	Array Dynamic Programming Backtracking Bit Manipulation Bitmask	—	—	—
Find Smallest Letter Greater Than Target Easy	Array Binary Search		—	—
Flood Fill Easy	Array Depth-First Search Breadth-First Search Matrix		—	—	—
Generate Parentheses Medium	String Dynamic Programming Backtracking		—	—	—
Get the Maximum Score Hard	Array Two Pointers Dynamic Programming Greedy		—	—	—
Insert into a Binary Search Tree Medium	Tree Binary Search Tree Binary Tree		—	—	—
Invert Binary Tree Easy	Tree Depth-First Search Breadth-First Search Binary Tree		—	—	—
K Closest Points to Origin Medium	Array Math Divide and Conquer Geometry Sorting Heap (Priority Queue) Quickselect		—	—	—
Kth Largest Element in an Array Medium	Array Divide and Conquer Sorting Heap (Priority Queue) Quickselect		—	—	—
Kth Smallest Element in a Sorted Matrix Medium	Array Binary Search Sorting Heap (Priority Queue) Matrix		—	—	—
Largest Divisible Subset Medium	Array Math Dynamic Programming Sorting		—	—	—
Letter Combinations of a Phone Number Medium	Hash Table String Backtracking			—	—
Linked List Cycle Easy	Hash Table Linked List Two Pointers		—	—	—
Longest Common Subsequence Medium	String Dynamic Programming		—	—	—
Longest Increasing Subsequence Medium	Array Binary Search Dynamic Programming		—	—	—
Longest Substring Without Repeating Characters Medium	Hash Table String Sliding Window	—		—	—
Lowest Common Ancestor of a Binary Search Tree Medium	Tree Depth-First Search Binary Search Tree Binary Tree			—	—
Lowest Common Ancestor of a Binary Tree Medium	Tree Depth-First Search Binary Tree		—	—	—
Maximal Square Medium	Array Dynamic Programming Matrix		—	—	—
Maximum Depth of Binary Tree Easy	Tree Depth-First Search Breadth-First Search Binary Tree			—	—
Merge k Sorted Lists Hard	Linked List Divide and Conquer Heap (Priority Queue) Merge Sort		—	—	—
Middle of the Linked List Easy	Linked List Two Pointers			—	—
Minimum Consecutive Cards to Pick Up Medium	Array Hash Table Sliding Window		—	—	—
Minimum Depth of Binary Tree Easy	Tree Depth-First Search Breadth-First Search Binary Tree		—	—	—
Minimum Path Sum Medium	Array Dynamic Programming Matrix		—	—	—
Minimum Window Substring Hard	Hash Table String Sliding Window		—	—	—
Move Zeroes Easy	Array Two Pointers	—		—	—
Number of Islands Medium	Array Depth-First Search Breadth-First Search Union-Find Matrix		—	—	—
Open the Lock Medium	Array Hash Table String Breadth-First Search		—	—	—
Palindrome Partitioning Medium	String Dynamic Programming Backtracking		—	—	—
Peak Index in a Mountain Array Medium	Array Binary Search		—	—
Perfect Squares Medium	Math Dynamic Programming Breadth-First Search		—	—	—
Permutations Medium	Array Backtracking		—	—	—
Predict the Winner Medium	Array Math Dynamic Programming Recursion Game Theory		—	—	—
Product of Array Except Self Medium	Array Prefix Sum		—	—	—
Range Sum Query - Immutable Easy	Array Design Prefix Sum		—	—	—
Remove Duplicates from Sorted Array Easy	Array Two Pointers	—		—
Reorganize String Medium	Hash Table String Greedy Sorting Heap (Priority Queue) Counting		—	—	—
Serialize and Deserialize Binary Tree Hard	String Tree Depth-First Search Breadth-First Search Design Binary Tree		—	—	—
Sliding Puzzle Hard	Array Dynamic Programming Backtracking Breadth-First Search Memoization Matrix		—	—	—
Sqrt(x) Easy	Math Binary Search		—	—
Subarray Sum Equals K Medium	Array Hash Table Prefix Sum		—	—	—
Subsets Medium	Array Backtracking Bit Manipulation		—	—	—
Subtree of Another Tree Easy	Tree Depth-First Search String Matching Binary Tree Hash Function		—	—	—
Triangle Medium	Array Dynamic Programming		—	—	—
Two Sum Easy	Array Hash Table		—
Two Sum II - Input Array Is Sorted Medium	Array Two Pointers Binary Search	—		—	—
Ugly Number II Medium	Hash Table Math Dynamic Programming Heap (Priority Queue)		—	—	—
Unique Paths Medium	Math Dynamic Programming Combinatorics			—	—
Valid Palindrome Easy	Two Pointers String	—		—	—
Validate Binary Search Tree Medium	Tree Depth-First Search Binary Search Tree Binary Tree		—	—	—
Word Break Medium	Array Hash Table String Dynamic Programming Trie Memoization		—	—	—
Word Ladder Hard	Hash Table String Breadth-First Search		—	—	—