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20 lines
452 B
20 lines
452 B
2 years ago
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#include <bits/stdc++.h>
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using namespace std;
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typedef long long LL;
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const int N = 40;
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LL c[N][N];
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int main() {
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// 预处理组合数
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for (int i = 0; i < N; i++)
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for (int j = 0; j <= i; j++)
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if (!j)
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c[i][j] = 1;
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else
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c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
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int n;
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cin >> n;
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// 卡特兰数
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cout << c[n * 2][n] / (n + 1) << endl;
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return 0;
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}
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