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