58 lines
1.4 KiB
C++
58 lines
1.4 KiB
C++
#include <iostream>
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#include <cstring>
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using namespace std;
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#define M 55
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#define LL long long
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#define FF(i, n) for(int i = 0; i < n; i++)
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int ans[M], mod, C[M][M];
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int ret[M][M], init[M][M];
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void ini(int n, int x)
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{
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memset(init, 0, sizeof(init));
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FF(i, n) FF(j, i+1)
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init[i][j] = (LL)x*C[i][j] % mod;
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FF(i, n) ans[i] = x;
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ans[n] = 0;
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init[n][n-1] = init[n][n] = 1;
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}
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void matmul(int a[][M], int b[][M], int n)
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{
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int tp[M][M] = {0};
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FF(i, n) FF(k, n) if(a[i][k]) FF(j, n) if(b[k][j])
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tp[i][j] = (tp[i][j] + (LL)a[i][k]*b[k][j]) % mod;
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FF(i, n) FF(j, n) a[i][j] = tp[i][j];
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}
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void matmul(int a[], int b[][M], int n)
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{
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int tp[M] = {0};
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FF(j, n) if(a[j]) FF(i, n) if(b[i][j])
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tp[i] = (tp[i] + (LL)a[j]*b[i][j]) % mod;
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FF(i, n) a[i] = tp[i];
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}
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void qmod(int n, int b)
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{
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FF(i, n) FF(j, n) ret[i][j] = (i==j);
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for( ; b; b >>= 1)
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{
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if (b & 1) matmul(ret, init, n);
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matmul(init, init, n);
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}
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}
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int main()
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{
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int i, j, n, x;
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while (cin >> n >> x >> mod, n >= 1)
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{
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for(i = 0; i <= x; i++)
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C[i][0] = C[i][i] = 1;
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for(i = 2; i <= x; i++)
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for(j = 1; j < i; j++)
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C[i][j] = ((LL)C[i-1][j-1]+C[i-1][j]) % mod;
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ini(x+1, x);
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qmod(x+2, n);
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matmul(ans, ret, x+2);
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cout << ans[x+1] << endl;
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}
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return 0;
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}
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