LCR180.文件组合

LCR180.文件组合

思路：滑动窗口

class Solution {
public:
    vector<vector<int>> fileCombination(int target) {
        int i=1,j=1;//左右边界,
        int sum=1;
        vector<vector<int>> res;
        while(i<=target/2){
            if(sum<target){
                j++;
                sum=sum+j;
            }else if(sum>target){
                sum=sum-i;
                i++;
            }else{//记录结果
                vector<int>tmp;
                for(int k=i;k<=j;k++){
                    tmp.push_back(k);
                }
                res.push_back(tmp);
                sum=sum-i;
                i++;//移动左边界
            }
        }
        return res;
    }
};