leetcode16 最接近的三数之和

class Solution {
public:
    int threeSumClosest(vector<int>& nums, int target) {
        sort(nums.begin(),nums.end());
        int ret=nums[0]+nums[1]+nums[2];
        int len=nums.size();
        int distance =abs(target-ret);
        if(ret==target)
            return target;
        for (int i = 0; i < len - 2; i++) {
            if(ret==target)
                return target;
            if((i>0)&&nums[i]==nums[i-1])
                continue;
            int l = i + 1;
            int r = len - 1;
            while (l < r) { //多组
                int tp = nums[i] + nums[l] + nums[r];
                if (abs(target-tp) < distance){
                    ret=tp;
                    distance=abs(target-tp);
                }
                if(tp>target)
                    while (l < r && nums[r] == nums[--r]);
                else if (tp<target)
                    while (l < r && nums[l] == nums[++l]);
                else 
                    return target; 
                }
            }
        return ret;
    }
};