Leetcode 16. 最接近的三数之和(3Sum Closest)

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解法一：
 

class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) 
    {
        int closest = nums[0] + nums[1] + nums[2];
        int diff = abs(closest - target);
        sort(nums.begin(), nums.end());
        for (int i = 0; i < nums.size() - 2; ++i) 
        {
            int left = i + 1, right = nums.size() - 1;
            while (left < right) 
            {
                int sum = nums[i] + nums[left] + nums[right];
                int newDiff = abs(sum - target);
                if (diff > newDiff) 
                {
                    diff = newDiff;
                    closest = sum;
                }
                if (sum < target) 
                	++left;
                else 
                	--right;
            }
        }
        return closest;
    }
};