leetcode-3Sum

class Solution {public:    vector<vector<int> > threeSum(vector<int> &num)     {        vector<vector<int>>result;        vector<int>vec;        int len = num.size();        //assert(len<3);        sort(num.begin(),num.end());        int j,k;        for(int i=0;i<len-2;i++)        {            if(i!=0&&num[i]==num[i-1])continue;            j=i+1;            k=len-1;            while(j<k)            {                if(j>i+1&&num[j]==num[j-1]){j++;continue;}                if(k<len-1&&num[k]==num[k+1]){k--;continue;}                if(num[i]+num[j]+num[k]>0)                {                    k--;                    continue;                }                                    if(num[i]+num[j]+num[k]<0)                {                    j++;                    continue;                }                            vec.push_back(num[i]);                vec.push_back(num[j]);                vec.push_back(num[k]);                result.push_back(vec);                vec.clear();                j++;                continue;            }                   }        return result;    }};