[LeetCode]16. 3Sum Closest

原题链接：https://leetcode.com/problems/3sum-closest/description/

 

我的实现：

class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) {
        sort(nums.begin(), nums.end());
        int size = nums.size();
        int minSum = nums[0] + nums[1] + nums[2];
        int maxSum = nums[size - 3] + nums[size - 2] + nums[size - 1];
        if (minSum >= target) return minSum;
        if (maxSum <= target) return maxSum;
        
        int result = minSum;
        for (int i = 0; i < size - 2; i++) {
            int start = i + 1;
            int end = size - 1;
            while (start < end) {
                int sum = nums[i] + nums[start] + nums[end];
                if (sum == target) return sum;
                else if (sum < target) {
                    start++;
                } else {
                    end--;
                }
                if (abs(sum - target) < abs(result - target))
                    result = sum;
            }
        }
        
        return result;
    }
};