Instead of splice, use swap and pop【JavaScript】

1 min readFeb 25, 2024

Hi, I’ve been immersed in leetcoding. Especially, I’m spending a lot of time improving bad code I wrote before. Today, I could improve O(N²) to O(N) and got trick to worth sharing.

First Leet code URL

Remove Element - LeetCode

Can you solve this real interview question? Remove Element - Level up your coding skills and quickly land a job. This…

leetcode.com

Originally, I wrote O(N²) code because for statement includes not only indexOf methods but splice(both of them are O(N)). It was too slow(108ms)

Improved Code

Remove Element — LeetCode

Can you solve this real interview question? Remove Element — Level up your coding skills and quickly land a job. This…

leetcode.com

This is the improved one. The trick is I used swap and pop (both of them are O(1)), instead of splice. As a result, the time complexity became 47ms!