19 lines
376 B
C++
19 lines
376 B
C++
#include <bits/stdc++.h>
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using namespace std;
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typedef long long LL;
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LL C(int n, int m) {
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LL a = 1, b = 1;
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for (int i = 0; i < m; i++) {
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a *= (n - i);
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b *= (m - i);
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}
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return a / b;
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}
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int main() {
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int n;
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cin >> n; // n过大会溢出，需要结合高精度
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printf("%lld\n", C(2 * n, n) / (n + 1));
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return 0;
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}
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