矩阵相乘
代码如下：
1 #include <cstdio> 2 #include <cstring> 3 4 struct matrix 5 { 6 int g[10][10]; 7 }mt; 8 9 int kk,m; 10 11 matrix multi(matrix a,matrix b) 12 { 13 matrix ans; 14 15 for(int i = 0;i < 10;i ++) 16 { 17 for(int j = 0;j < 10;j ++) 18 { 19 int t = 0; 20 for(int u = 0;u < 10;u ++) 21 { 22 t += a.g[i][u] * b.g[u][j]; 23 t = t % m; 24 } 25 ans.g[i][j] = t % m; 26 } 27 } 28 29 return ans; 30 } 31 32 int solve(int k) 33 { 34 matrix temp = mt; 35 matrix ans; 36 memset(ans.g,0,sizeof(ans.g)); 37 for(int i = 0;i < 10;i ++) 38 { 39 ans.g[0][i] = i; 40 } 41 42 for(int i = 0;k != 0;i ++) 43 { 44 if(k & (1 << i)) 45 ans = multi(ans,temp); 46 temp = multi(temp,temp); 47 k = k & (~(1 << i) ); 48 } 49 50 return ans.g[0][9]; 51 } 52 53 int main() 54 { 55 while(scanf("%d%d",&kk,&m) == 2) 56 { 57 memset(mt.g,0,sizeof(mt.g)); 58 for(int i = 0;i < 10;i ++) 59 { 60 int a; 61 scanf("%d",&a); 62 mt.g[9 - i][9] = a; 63 if(i < 9) 64 mt.g[9 - i][8 - i] = 1; 65 } 66 67 if(kk < 10) 68 { 69 printf("%d\n",kk % m); 70 continue; 71 } 72 73 printf("%d\n",solve(kk-9)%m); 74 } 75 76 return 0; 77 }