hdu 5411 CRB and Puzzle（矩阵快速幂）

题目链接：hdu 5411 CRB and Puzzle

根据给定边都建矩阵，并且再加上一个终止符，所有puzzle可以指向终止符。

#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;
const int maxn = 55;
const int mod = 2015;

struct Mat {
int r, c, arr[maxn][maxn];
Mat (int r = 0, int c = 0): r(r), c(c) { memset(arr, 0, sizeof(arr)); }

Mat operator * (const Mat& u) {
Mat ret(r, u.c);
for (int k = 0; k < c; k++) {
for (int i = 0; i < r; i++) {
if (arr[i][k] == 0) continue;
for (int j = 0; j < u.c; j++)
ret.arr[i][j] = (ret.arr[i][j] + arr[i][k] * u.arr[k][j]) % mod;
}
}
return ret;
}

/*
Mat operator + (const Mat& u) {
Mat ret(r, c);
for (int i = 0; i < r; i++)
for (int j = 0; j < c; j++)
ret.arr[i][j] = (arr[i][j] + u.arr[i][j]) % mod;
return ret;
}
*/
};

int N, M;

Mat pow_mat (Mat x, int n) {

Mat ret(N + 1, 1);
for (int i = 0; i <= N; i++)
ret.arr[i][0] = 1;

while (n) {
if (n&1)
ret = x * ret;
x = x * x;
n >>= 1;
}
return ret;
}

void put (Mat u) {
for (int i = 0; i < u.r; i++) {
printf("%d", u.arr[i][0]);
for (int j = 1; j < u.c; j++)
printf(" %d", u.arr[i][j]);
printf("\n");
}
}

int main () {
int cas;
scanf("%d", &cas);
while (cas--) {
scanf("%d%d", &N, &M);
int n, x;
Mat T(N + 1, N + 1);
for (int i = 0; i < N; i++) {
scanf("%d", &n);
for (int j = 0; j < n; j++) {
scanf("%d", &x);
T.arr[x-1][i] = 1;
}
T.arr
[i] = 1;
}
T.arr

= 1;

Mat ans = pow_mat(T, M-1);
//put(ans);
int ret = 0;
for (int i = 0; i <= N; i++) {
ret = (ret + ans.arr[i][0]) % mod;
}
printf("%d\n", ret);
}
return 0;
}