|
@@ -0,0 +1,18 @@
|
|
|
|
|
+#include <cmath>
|
|
|
|
|
+
|
|
|
|
|
+class Solution {
|
|
|
|
|
+public:
|
|
|
|
|
+ int consecutiveNumbersSum(int N) {
|
|
|
|
|
+ // Assume that we pick n elements start from x, then
|
|
|
|
|
+ // for (x + (n - 1) * x) * n / 2 == N,
|
|
|
|
|
+ // ie. n * x + n * (n - 1) / 2 == N.
|
|
|
|
|
+ // Just check for some n, we have valid x.
|
|
|
|
|
+ int cnt = 0;
|
|
|
|
|
+ for (int n = 1; ; n++) {
|
|
|
|
|
+ int nx = N - n * (n - 1) / 2;
|
|
|
|
|
+ if (nx < n) break;
|
|
|
|
|
+ if (nx % n == 0) cnt++;
|
|
|
|
|
+ }
|
|
|
|
|
+ return cnt;
|
|
|
|
|
+ }
|
|
|
|
|
+};
|
