Given an array
nums of n integers and an integer
target, find three integers in
nums such that the sum is closest to
target. Return the sum of the three integers. You may assume that each input would have exactly one solution.
Input: nums = [-1,2,1,-4], target = 1 Output: 2 Explanation: The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
3 <= nums.length <= 10^3
-10^3 <= nums[i] <= 10^3
-10^4 <= target <= 10^4
The main gist of this question is to reduce the 3 sum problem into a 2 sum problem and using the two-pointer approach to solve it.
Time Complexity: O(n^2)
Space Complexity: O(1)