[Leetcode]3Sum Closest

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).

和3sum 的解法类似

class Solution {public:    int threeSumClosest(vector<int> &num, int target) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        int ret;int magin=INT_MAX;sort(num.begin(),num.end());for(int i = 0 ; i < num.size(); i++ ){if( i > 0 && num[i-1] == num[i] )continue;int j = i + 1;int k = num.size() - 1;while(j<k){if( j > i + 1 && num[j] == num[j-1]){j++;continue;}if( k< num.size() - 1 && num[k] == num[k+1]){k--;continue;}int sum = num[i]+num[j]+num[k];if(abs(sum-target)<magin){magin=abs(sum-target);ret=sum;}if(sum>target){k--;}else{j++;}}//while}//forreturn ret;    }};