← All problems

16. 3sum Closest

MediumOpen on LeetCodeProblem statement

Problem Statement

16. 3Sum Closest

Medium


Given an integer array nums of length n 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.

 

Example 1:

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).

Example 2:

Input: nums = [0,0,0], target = 1
Output: 0
Explanation: The sum that is closest to the target is 0. (0 + 0 + 0 = 0).

 

Constraints:

C++

Source file
class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) {
        int diff=INT_MAX, res=0;
        sort(nums.begin(), nums.end());
        for(int i=0; i<nums.size()-2; i++){
            int j=i+1, k=nums.size()-1;
            int newTarget = target-nums[i];
            while(j<k){
                int newDiff = newTarget - nums[j] - nums[k];
                if(abs(newDiff)<diff){
                    res=target-newDiff;
                    if(diff==abs(newDiff))
                        return res;
                    diff=abs(newDiff);
                }
                newDiff<0?k--:j++;
            }
        }
        return res;
    }
};