Easy data structure and algorithm practice puzzle.
Given two strings s and t, return true if t uses exactly the same letters as s, the same number of times. Count each letter in s, then subtract each letter in t. If every count lands back at zero, it's an anagram. If the lengths differ, you can stop right away. A frequency map like this is behind spell checkers and word games.
Solve it three ways: snap the jigsaw pieces together, fill in the blanks, or type it from scratch against the tests. This one is free.
Every line of the solution comes with a note explaining why it is there, and a step by step replay shows the code running. At level 3, where you type it yourself, you can ask for an AI mock interview on this problem that ends with a hiring manager's scorecard.
Then grow it into a real project with the Software Engineer button: this puzzle becomes the Document Fuzzy Matcher, a pipeline you can run and download. See every Software Engineer project.
Browse all 576 puzzles