Given an integer n, return the number of ways you can write n as the sum of consecutive positive integers.
Example 1:
Input: n = 5
Output: 2
Explanation: 5 = 2 + 3
Example 2:
Input: n = 9
Output: 3
Explanation: 9 = 4 + 5 = 2 + 3 + 4
Example 3:
Input: n = 15
Output: 4
Explanation: 15 = 8 + 7 = 4 + 5 + 6 = 1 + 2 + 3 + 4 + 5
Constraints:
1 <= n <= 109
就是个数学题，不说了
class Solution {
public int consecutiveNumbersSum(int N) {
int ans = 0;
for (int i = 1; i * (i - 1) / 2 < N; ++i)
if ((N - i * (i - 1) / 2) % i == 0)
++ans;
return ans;
}
}