16 3Sum Closest(输出距离target最近的三个数的和Medium)

 1 class Solution {
 2 public:
 3     int threeSumClosest(vector<int>& nums, int target) {
 4         int size=nums.size();
 5         if(size<3)return 0;
 6         int j,k;
 7         int distance,temp,answer;
 8         sort(nums.begin(),nums.end());
 9         distance=abs(nums[0]+nums[1]+nums[2]-target);
10         for(int i=0;i<size-2;++i){
11             j=i+1;
12             k=size-1;
13             while(j<k){
14                 temp=nums[i]+nums[j]+nums[k];
15                 if(distance>=abs(temp-target)){    //加等号，是解决nums长度为3的情况
16                     distance=abs(temp-target);
17                     answer=temp;
18                 }
19                 if(temp-target>0)k--;
20                 else if(temp-target<0)j++;
21                 else return target;
22             }
23         }
24         return answer;
25     }
26 };