13 lines
410 B
C++
13 lines
410 B
C++
#include <iostream>
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using namespace std;
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typedef long long LL;
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int main() {
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LL f[21] = {0, 0, 1}; //这个初始化很牛B的样子,放过头雁打二雁，而且f[1]=0,f[2]=1
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//错排公式,预处理
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for (int i = 3; i < 21; i++) f[i] = (i - 1) * (f[i - 1] + f[i - 2]);
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for (int i = 1; i <= 20; i++)
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cout << "i=" << i << ",f[" << i << "]=" << f[i] << endl;
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return 0;
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} |