//0054和为S的连续正数序列 
class Solution {
public:
    //开始没有想到求和公式，单调性也没有想到(菜了菜了
    //暴力的二分一会补
    vector<vector<int> > findContinuousSequence(int sum) {
        vector<vector<int> >ans; ans.clear();
        int l = 1, h = 1, s = 1;

        //这里对 l <= h 可以不做控制
        for (;l < sum && l <= h; ++l) {
            while (s < sum) {
                s += ++h;
            }
            if (s == sum) {
                vector<int>buff; buff.clear();
                for (int i = l; i <= h; ++i) buff.push_back(i);

                ans.push_back(buff);
            }
            s -= l;
        }
        return ans;
    }
};