Code runner
DSA challenges
Write real code, run it against hidden test cases, and earn XP for every case you pass.
20 challenges · 10 easy · 10 medium · 0 hard
medium
Anagram Check
strings
medium
Binary Search
searching
easy
Count Vowels in a String
strings
easy
Factorial
math
medium
Find the Missing Number
math
medium
First Non-Repeating Character
strings
easy
FizzBuzz
loops
medium
Longest Common Prefix
strings
easy
Maximum Element of an Array
arrays
medium
Maximum Subarray Sum (Kadane)
arrays
medium
Merge Two Sorted Arrays
arrays
medium
Move Zeros to the End
two-pointers
easy
Nth Fibonacci Number
dp
easy
Palindrome Check
strings
easy
Prime Number Check
math
medium
Remove Duplicates from a Sorted Array
arrays
easy
Reverse a String
strings
easy
Sum of Digits
math
easy
Two Sum
arrays
medium
Valid Parentheses
stack
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