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Title
Difficulty
Random
49 problems
1
Two Sum
easy
Arrays & Hashing
2
Contains Duplicate
easy
Arrays & Hashing
3
Best Time to Buy and Sell Stock
easy
Arrays & Hashing
4
Valid Parentheses
easy
Arrays & Hashing
5
Binary Search
easy
Binary Search
6
Climbing Stairs
easy
Dynamic Programming
7
House Robber
medium
Dynamic Programming
8
Maximum Subarray
medium
Arrays & Hashing
9
Reverse Linked List
easy
Linked Lists
10
Number of Islands
medium
Graphs
11
Valid Palindrome
easy
Two Pointers
12
Two Sum II - Input Array Is Sorted
medium
Two Pointers
13
3Sum
medium
Two Pointers
14
Container With Most Water
medium
Two Pointers
15
Longest Substring Without Repeating Characters
medium
Sliding Window
16
Permutation in String
medium
Sliding Window
17
Minimum Window Substring
hard
Sliding Window
18
Search in Rotated Sorted Array
medium
Binary Search
19
Find Minimum in Rotated Sorted Array
medium
Binary Search
20
Merge Two Sorted Lists
easy
Linked Lists
21
Linked List Cycle
easy
Linked Lists
22
Maximum Depth of Binary Tree
easy
Trees
23
Invert Binary Tree
easy
Trees
24
Binary Tree Level Order Traversal
medium
Trees
25
Validate Binary Search Tree
medium
Trees
26
Implement Trie (Prefix Tree)
medium
Tries
27
Word Search
medium
Tries
28
Kth Largest Element in an Array
medium
Heap & Priority Queue
29
Top K Frequent Elements
medium
Heap & Priority Queue
30
Last Stone Weight
easy
Heap & Priority Queue
31
Subsets
medium
Backtracking
32
Combination Sum
medium
Backtracking
33
Permutations
medium
Backtracking
34
Course Schedule
medium
Graphs
35
Clone Graph
medium
Graphs
36
Coin Change
medium
Dynamic Programming
37
Longest Common Subsequence
medium
Dynamic Programming
38
Jump Game
medium
Greedy
39
Gas Station
medium
Greedy
40
Single Number
easy
Bit Manipulation
41
Number of 1 Bits
easy
Bit Manipulation
42
Counting Bits
easy
Bit Manipulation
43
Missing Number
easy
Bit Manipulation
44
Generate Parentheses
medium
Backtracking
45
Letter Combinations of a Phone Number
medium
Backtracking
46
Pow(x, n)
medium
Recursion
47
Fibonacci Number
easy
Recursion
48
Pascal's Triangle
easy
Recursion
49
Reverse Integer
medium
Recursion