leetcode829 连续整数求和

思路：

数论。参考了https://leetcode.cn/problems/consecutive-numbers-sum/solution/by-ac_oier-220q/。

实现：

class Solution {
public:
    int consecutiveNumbersSum(int n) {
        int res=0;
        for(int i=1;i*i<2*n;i++){
            if(2*n%i==0){
                int j=2*n/i-i+1;
                if(j%2==0 and j>=2){
                    res++;
                }
            }
        }
        return res;
    }
};