bzoj1898: [Zjoi2004]Swamp 沼泽鳄鱼

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矩阵乘法

每12个单位时间是个循环

前K/12个单位时间用快速幂，后K%12个单位时间用裸矩阵乘法

#include <cstdio>#include <cstring>#define MAXN 53#define MOD 10000int n, m, s, t, nf;long T;int a[12][MAXN][MAXN];int b[MAXN][MAXN], tmp[MAXN][MAXN];void multiply(int a[MAXN][MAXN], int b[MAXN][MAXN], int f[MAXN][MAXN]){    memset(f, 0, sizeof(int) * MAXN * MAXN);    for (int i = 0; i < n; ++i)        for (int j = 0; j < n; ++j)            for (int k = 0; k < n; ++k)                f[i][j] = (f[i][j] + a[i][k] * b[k][j] % MOD) % MOD;}void power(int a[MAXN][MAXN], int b, int f[MAXN][MAXN]){    if (b == 0)    {        memset(f, 0, sizeof(int) * MAXN * MAXN);        for (int i = 0; i < n; ++i)            f[i][i] = 1;        return;    }    if (b == 1)    {        memcpy(f, a, sizeof(int) * MAXN * MAXN);        return;    }    int t[MAXN][MAXN];    power(a, b / 2, f);    multiply(f, f, t);    if (b % 2 == 0)        memcpy(f, t, sizeof(int) * MAXN * MAXN);    else        multiply(t, a, f);}int main(){    scanf("%d%d%d%d%ld", &n, &m, &s, &t, &T);    memset(a, 0, sizeof(a));    while (m--)    {        int u, v;        scanf("%d%d", &u, &v);        for (int i = 0; i < 12; ++i)            a[i][u][v] = a[i][v][u] = 1;    }    scanf("%d", &nf);    while (nf--)    {        int l, x[4];        scanf("%d", &l);        for (int i = 0; i < l; ++i)            scanf("%d", &x[i]);        for (int i = 0; i < 12; ++i)            for (int j = 0; j < n; ++j)            {                a[i][j][x[(i + 1) % l]] = 0;                a[i][x[i % l]][j] = 0;            }    }    memcpy(b, a[0], sizeof(b));    for (int i = 1; i < 12; ++i)    {        multiply(b, a[i], tmp);        memcpy(b, tmp, sizeof(b));    }    power(b, T / 12, tmp);    memcpy(b, tmp, sizeof(b));    for (int i = 0; i < T % 12; ++i)    {        multiply(b, a[i], tmp);        memcpy(b, tmp, sizeof(b));    }    printf("%d\n", b[s][t]);    return 0;}

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