HackerRank Certification Solutions

These are the questions from the HackerRank skills certification tests I have taken, one page per question. Each page explains what the question asks in plain words, gives a solution I have run against sample data, and lists the mistakes that usually fail the hidden test cases.

Use them to understand the approach, then write your own answer in the test. HackerRank checks your code against hidden cases, so a copied answer you don’t understand breaks the moment the question changes slightly.