4sum

Tags: two pointer

Problem Statement:
You are given an integer array nums of size n, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:

• 0 <= a, b, c, d < n
• a, b, c, and d are distinct.
• nums[a] + nums[b] + nums[c] + nums[d] == target

Intuition:
Read 3sum if you are completely blank

Code: