4Sum
Given an integer array nums and an integer target, return all unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:
0 <= a, b, c, d < nums.lengtha,b,c, anddare distinct indicesnums[a] + nums[b] + nums[c] + nums[d] == target
The solution set must not contain duplicate quadruplets. You may return the answer in any order.
Example 1
Input
nums = [1,0,-1,0,-2,2], target = 0Output
[[-2,-1,1,2],[-2,0,0,2],[-1,0,0,1]]The three listed quadruplets are the only unique combinations of four numbers that sum to 0.
Example 2
Input
nums = [2,2,2,2,2], target = 8Output
[[2,2,2,2]]The only quadruplet that sums to 8 uses four of the 2s.
Constraints
- 1 <= nums.length <= 200
- -10^9 <= nums[i] <= 10^9
- -10^9 <= target <= 10^9