Programming Challenges

Strengthen your problem-solving skills with language-neutral challenges you can solve in Python, C++, or C#. Every submission is checked by automated tests and reviewed by AI.

  • Python · C++ · C#
  • Automated tests
  • AI code review
  • Community solutions
Learning path
150
Challenges
2
Solutions shared
3
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All challenges

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28 challenges
Easy

Remove Duplicates

Keep only the first occurrence of each value.

ArraysBeginnerSetsStudent-beginner
No solutions yet
Easy

Roman Numeral Value

Convert a Roman numeral to a number.

BeginnerLookup-tablesStringsStudent-beginner
No solutions yet
Easy

Fibonacci Number

Return the n-th Fibonacci number.

BeginnerLoopsSequencesStudent-beginner
No solutions yet
Easy

Missing Number

Find the one number missing from 0..n.

ArraysBeginnerStudent-beginnermath
No solutions yet
Easy

Sum an Array

Add up all values in a list.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Array Minimum

Find the smallest value in a list.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Rotate Array

Rotate a list to the right by some steps.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Array Average

Compute the average of a list of numbers.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Second Largest Value

Find the second largest distinct value.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Cash: Fewest Coins

Give change with as few U.S. coins as possible.

BeginnerGreedyStudent-beginnermath
No solutions yet
Easy

Array Maximum

Find the largest value in a list.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Prime Number Check

Decide whether a number is prime.

BeginnerLoopsNumbersStudent-beginner
No solutions yet
Easy

Character Frequency

Count how often each character appears.

BeginnerDictionariesStringsStudent-beginner
No solutions yet
Easy

Move Zeroes

Move every zero to the end while keeping the other order.

ArraysBeginnerStudent-beginner
No solutions yet
Easy

Greatest Common Divisor

Find the largest number that divides both values.

BeginnerNumbersStudent-beginner
No solutions yet
Easy

First Unique Character

Find the first character that appears only once.

BeginnerDictionariesStringsStudent-beginner
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Easy

Armstrong Number

Check whether a number equals the sum of its digits raised to the digit count.

BeginnerNumbersStudent-beginner
No solutions yet
Easy

Anagram Check

Check whether two phrases use the same letters.

BeginnerStringsStudent-beginner
No solutions yet