169. 4 Sum
Given an integer array nums and an integer target. Return all quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:
- a, b, c, d are all distinct valid indices of nums.
- nums[a] + nums[b] + nums[c] + nums[d] == target.
Notice that the solution set must not contain duplicate quadruplets. One element can be a part of multiple quadruplets. The output and the quadruplets can be returned in any order.
Example 1:
Input: nums = [1, -2, 3, 5, 7, 9], target = 7
Output: [[-2, 1, 3, 5]]
Explanation:
nums[1] + nums[0] + nums[2] + nums[3] = 7
Example 2:
Input: nums = [7, -7, 1, 2, 14, 3], target = 9
Output: []
Explanation:
No quadruplets are present which add upto 9
Now Your Turn!
Pick the correct output for the given inputInput: nums = [1, 1, 3, 4, -3], target = 5
(Give answer with the output and quadruplets sorted in ascending order)
Still unsure what the problem is asking ?
Let’s go through a few more examples, step by step, to make it clearer.
Constraints:
- 1 <= nums.length <= 200
- -104 <= nums[i] <= 104
- -104 <= target <= 104