26 lines
693 B
C++
26 lines
693 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 110;
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int n, m;
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int f[N][N];
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int main() {
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cin >> n >> m;
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// 边界：第0次传球，第1个人获得球的机会数
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f[0][1] = 1;
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// 传m次球
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for (int i = 1; i <= m; i++) {
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for (int j = 1; j <= n; j++) {
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if (j == 1)
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f[i][j] = f[i - 1][j + 1] + f[i - 1][n];
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else if (j == n)
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f[i][j] = f[i - 1][j - 1] + f[i - 1][1];
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else
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f[i][j] = f[i - 1][j - 1] + f[i - 1][j + 1];
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}
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}
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// 经过m次传球，球回到第1个人手中的机会数
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cout << f[m][1] << endl;
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return 0;
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} |