leetcode 16 3Sum Closest

Question：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).

class Solution {
public:
    int threeSumClosest(vector& nums, int target)
    {
    }
};

本题还是考察夹逼

class Solution {
public:
    int threeSumClosest(vector& nums, int target)
    {
        sort( nums.begin(), nums.end() );
        int size = nums.size();
        int result=0;
        int min_gap=INT32_MAX;
        auto last=nums.end();
        
        
        for (auto i=nums.begin(); i<(last-2); i++)
        {
            if( i>nums.begin() && *i == *(i-1) ) continue;
            
            auto j=(i+1);
            auto k=last-1;
            
            while( j