leetcode 3sum closest

链接：https://oj.leetcode.com/problems/3sum-closest/

题意：在数组中求出3个数sum和最接近target 时，sum为返回值

1.和上道题思路类似

2.比较的时候注意用绝对值abs

代码：

<pre name="code" class="cpp">class Solution {
public:
    int threeSumClosest(vector<int> &num, int target) {
        sort(num.begin(),num.end());
        int result = 10000;
        int tmp1,tmp2;
        if(num.size()<3)
            return 0;
        for(int i = 0;i < num.size();i++){
            if(i!=0 && num[i] ==num[i-1]) continue;
            int j = i + 1, k = num.size()-1;
            int sum;
            while(j < k){
                sum = num[i] + num[j] + num[k];
                tmp1 = abs(target - sum);
                tmp2 = abs(target - result);
                if( tmp1 < tmp2) result = sum;
                if(sum < target) j++;
                else k--;
            }
        }
        return result;
    }
};