剑指 Offer 57 - II：和为s的连续正数序列

输入：target = 9
输出：[[2,3,4],[4,5]]

输入：target = 15
输出：[[1,2,3,4,5],[4,5,6],[7,8]]

class Solution {
public:
    vector<vector<int>> findContinuousSequence(int target) {
        int left=1;//左指针
        int right=2;//右指针
        int sum=3;//记录当前的总和
        vector<vector<int>> res;
        while(2*left<target){//如果2倍的左指针都大于target，那么左+右指针一定大于target
            if(sum<target){
                right++;
                sum+=right;
            }
            else if(sum>target){
                sum-=left;
                left++;
            }
            else{
                vector<int> tmp;
                for(int i=left;i<=right;i++){
                    tmp.push_back(i);
                }
                res.push_back(tmp);
                sum-=left;
                left++;
            }
        }
        return res;
    }
};