Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly one solution.
For example, given array S = {-1 2 1 -4}, and target = 1. The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).code
class Solution { public: int threeSumClosest(vector<int>& nums, int target) { sort(nums.begin(), nums.end()); int n = nums.size(); int positive = INT_MAX, negative = INT_MAX; for(int i = 0; i < n; i++){ int L = i + 1, R = n - 1; int twoTarget = target - nums[i]; while(L < R){ if(nums[L] + nums[R] > twoTarget){ positive = min(positive, nums[L] + nums[R] - twoTarget); R--; }else{ negative = min(negative, twoTarget - nums[L] - nums[R]); L++; } } } if(positive > negative) return target - negative; else return target + positive; } };
