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18 4Sum Leetcode Problem Javascript Solution

4Sum
Medium
Given an array nums of n integers and an integer target, are there elements a, b, c, and d in nums such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of target.
Note:
The solution set must not contain duplicate quadruplets.
Example:
Given array nums = [1, 0, -1, 0, -2, 2], and target = 0.

A solution set is:
[
  [-1,  0, 0, 1],
  [-2, -1, 1, 2],
  [-2,  0, 0, 2]
]
var fourSum = function(nums, target) {
  nums = nums.sort();
  const result = [];
  const n = nums.length;
  let l;
  for(let i=0; i<n-3; i++) {
    for(let j=i+1; j<n-2; j++) {
      for(let k=j+1; k<n-1; k++) {
        for(let l=k+1; l<n; l++) {
          if (nums[i]+nums[j]+nums[k]+nums[l] === target) {
            result.push([nums[i], nums[j], nums[k], nums[l]])
          }
        }
      }
    }
  }
  return Array.from(new Set(result.map(JSON.stringify))).map(JSON.parse);
};

console.log(fourSum([-5,5,4,-3,0,0,4,-2], 4));
Run the code here: https://repl.it/@VinitKhandelwal/18-foursum-leetcode

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