Solve problems with JavaScript

Recursive approach

Divide and conquer

Use 2 hash tables

Insert and keep the array sorted

Dynamic programming, top-down approach

Memoized recursion, somewhat similar to "Longest common subsequence"

Hash table, sort by occurences then greedily remove

Flatten and sort

Flat, reverse, and pop

Memoized recursion

Sort with custom comparator

Find the longest contiguos subsequences with K zeros at most