Coding Practice
Sharpen your skills on real challenges — write a solution in the browser and have it judged against the tests.
Difficulty
Topic
Warmup
1 problemEasy
11 problemsReverse a String
Easy- strings
FizzBuzz
Easy- math
- simulation
Count the Vowels
Easy- strings
Maximum in a List
Easy- arrays
Sum of Digits
Easy- math
Word Count
Easy- strings
Greatest Common Divisor
Easy- math
- number-theory
Power of Two
Easy- bit-manipulation
- math
Factorial
Easy- math
Nth Fibonacci Number
Easy- dynamic-programming
- math
Reverse Integer
Easy- math
Medium
16 problemsValid Anagram
Medium- strings
- hashing
Binary Search
Medium- arrays
- searching
Run-Length Encoding
Medium- strings
Second Largest
Medium- arrays
Merge Sorted Arrays
Medium- arrays
- two-pointers
First Non-Repeating Character
Medium- strings
- hashing
Maximum Subarray Sum
Medium- arrays
- dynamic-programming
Count Distinct Values
Medium- arrays
- hashing
Roman to Integer
Medium- strings
- math
Matrix Diagonal Sum
Medium- matrix
Move Zeroes
Medium- arrays
- two-pointers
Majority Element
Medium- arrays
Product of Array Except Self
Medium- arrays
- prefix-sums
Sort Colors
Medium- arrays
- sorting
Climbing Stairs
Medium- dynamic-programming
Container With Most Water
Medium- arrays
- two-pointers
Hard
6 problemsCoin Change
Hard- dynamic-programming
Longest Increasing Subsequence
Hard- dynamic-programming
Edit Distance
Hard- dynamic-programming
- strings
Number of Islands
Hard- graphs
- grid
Trapping Rain Water
Hard- arrays
- two-pointers
Longest Common Subsequence
Hard- dynamic-programming
- strings
Stay in the loop
Get notified as problems and judging launch
Bring us the problem, not a perfect specification
Tell us what needs to change, who it affects and any important deadline. We will review the context and reply with useful next questions.
- 01Share contextDescribe the workflow, constraint or risk.
- 02Clarify togetherWe identify missing facts and useful options.
- 03Choose a startAgree a focused assessment or delivery step.