Challenges
Reverse a String
Difficulty: Easy
Write a function that takes a string as input and returns the string reversed.
Example:
Input: 'hello' Output: 'olleh'
Input: 'world' Output: 'dlrow'
Hints
0 of 4 revealed
Two Sum
Difficulty: Easy
Palindrome Check
Difficulty: Easy
FizzBuzz
Difficulty: Easy
Find Maximum
Difficulty: Easy
Factorial
Difficulty: Easy
Fibonacci Number
Difficulty: Easy
Premium Challenge
Remove Duplicates from Sorted Array
Difficulty: Easy
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Count Primes
Difficulty: Easy
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Reverse Linked List
Difficulty: Easy
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Climbing Stairs
Difficulty: Easy
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Power of Two
Difficulty: Easy
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Single Number
Difficulty: Easy
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Intersection of Two Arrays
Difficulty: Easy
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Move Zeroes
Difficulty: Easy
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Valid Parentheses
Difficulty: Easy
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Merge Two Sorted Lists
Difficulty: Easy
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Binary Search
Difficulty: Medium
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Longest Substring Without Repeating Characters
Difficulty: Medium
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Merge Intervals
Difficulty: Medium
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Group Anagrams
Difficulty: Medium
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Container With Most Water
Difficulty: Medium
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Longest Palindromic Substring
Difficulty: Medium
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Kth Largest Element in an Array
Difficulty: Medium
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Search in Rotated Sorted Array
Difficulty: Medium
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Generate Parentheses
Difficulty: Medium
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Course Schedule
Difficulty: Medium
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Add Two Numbers
Difficulty: Medium
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Minimum Path Sum
Difficulty: Medium
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Subarray Sum Equals K
Difficulty: Medium
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Set Matrix Zeroes
Difficulty: Medium
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Spiral Matrix
Difficulty: Medium
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Combination Sum
Difficulty: Medium
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Jump Game
Difficulty: Medium
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Unique Paths
Difficulty: Medium
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Sort Colors
Difficulty: Medium
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Permutations
Difficulty: Medium
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Rotate Array
Difficulty: Medium
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Top K Frequent Elements
Difficulty: Medium
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LRU Cache
Difficulty: Medium
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Median of Two Sorted Arrays
Difficulty: Hard
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Trapping Rain Water
Difficulty: Hard
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Word Ladder
Difficulty: Hard
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Regular Expression Matching
Difficulty: Hard
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Sudoku Solver
Difficulty: Hard
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Longest Valid Parentheses
Difficulty: Hard
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N-Queens
Difficulty: Hard
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First Missing Positive
Difficulty: Hard
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Wildcard Matching
Difficulty: Hard
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Maximal Rectangle
Difficulty: Hard
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Your Solution
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