【HDOJ】2157 How many ways??

矩阵乘法，用DP做各种wa，后来发现原因了。

 #include <stdio.h>
 #include <string.h>

 typedef struct {
     int map[][];
 } matrix_st;

 matrix_st res, org;
 int n, m;

 matrix_st multiply(matrix_st a, matrix_st b) {
     int i, j, k;
     matrix_st c;

     for (i=; i<n; ++i) {
         for (j=; j<n; ++j) {
             c.map[i][j] = ;
             for (k=; k<n; ++k)
                 c.map[i][j] += a.map[i][k] * b.map[k][j];
             c.map[i][j] %= ;
         }
     }

     return c;
 }

 void calc(matrix_st org, int k) {
     while (k) {
         if (k & )
             res = multiply(res, org);
         k >>= ;
         org = multiply(org, org);
     }
 }

 int main() {
     int t, i, j, k;

     while (scanf("%d %d", &n, &m)!=EOF && (n||m)) {
         memset(org.map, , sizeof(org.map));
         for (i=; i<m; ++i) {
             scanf("%d %d", &j, &k);
             org.map[j][k] = ;
         }
         scanf("%d", &t);
         while (t--) {
             memset(res.map, , sizeof(res.map));
             for (i=; i<n; ++i)
                 res.map[i][i] = ;
             scanf("%d %d %d", &i, &j, &k);
             calc(org, k);
             printf("%d\n", res.map[i][j]);
         }

     }

     return ;
 }