3Sum Closest

tags:two pointers

解法思想见：http://www.sigmainfy.com/blog/summary-of-ksum-problems.html

代码：

<span style="font-size:18px;">class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) {
        sort(nums.begin(), nums.end());
        int size = nums.size(), min = INT_MAX;
        int temp, i, j, a;
        int res = nums[0]+nums[1]+nums[size-1];
        for(int k = 0; k <= size-3; k++){
            temp = target-nums[k];
            i = k+1;
            j = size-1;
            while(i<j){
                a = nums[i]+nums[j]-temp;
                if(a==0) return a + target;
                if(a>0) j--;
                else i++;
                if(abs(a)<min){
                    min = abs(a);
                    res = a + target;
                }
            }
        }
        return res;
    }
};</span>