The Must-Solve 150.
Every question is a real implementation, debugging or architecture task. Work through the levels in order, or jump straight to what your next interview needs.
10 of 150 questions
Easy
25 questions, 10–20 minutes each
Warm-ups you should solve without help.
Strings, objects & algorithms
Hash maps, stacks and object utilities that show up in every warm-up round.
- 11Reverse words in a sentence
- 12Valid parentheses using a stackFree
- 13Two Sum using a hash map
- 14Check whether two strings are anagrams
- 15Find the first non-repeating character
- 16Remove duplicate items from an array
- 17Implement
chunk(array, size) - 18Implement a basic
deepEqual()for nested arrays and objects - 19Implement
set(object, "a.b.c", value) - 20Merge two sorted arrays