UVA-10689 Yet another Number Sequence （矩阵二分幂模板）

 1 # include<iostream>
 2 # include<cstdio>
 3 # include<cstring>
 4 # include<algorithm>
 5 using namespace std;
 6 struct matrix
 7 {
 8     int r,c,m[3][3];
 9     matrix(int _r,int _c):r(_r),c(_c){}
10 };
11 int a,b,n,m;
12 int mod[4]={10,100,1000,10000};
13 matrix multiply(matrix a,matrix b)
14 {
15     matrix c(a.r,b.c);
16     for(int i=1;i<=c.r;++i){
17         for(int j=1;j<=c.c;++j){
18             c.m[i][j]=0;
19             for(int k=1;k<=a.c;++k){
20                 c.m[i][j]+=(a.m[i][k]*b.m[k][j]);
21                 c.m[i][j]%=mod[m-1];
22             }
23         }
24     }
25     return c;
26 }
27 matrix matrix_pow(matrix a,int k)
28 {
29     if(k==0){
30         for(int i=1;i<=a.r;++i)
31             for(int j=1;j<=a.c;++j)
32                 a.m[i][j]=(i==j)?1:0;
33         return a;
34     }
35     if(k==1)
36         return a;
37     matrix res=matrix_pow(a,k/2);
38     res=multiply(res,res);
39     if(k&1)
40         res=multiply(res,a);
41     return res;
42 }
43 int main()
44 {
45     int T;
46     scanf("%d",&T);
47     while(T--)
48     {
49         scanf("%d%d%d%d",&a,&b,&n,&m);
50         if(n==0){
51             printf("%d\n",a%mod[m-1]);
52             continue;
53         }
54         matrix mat(2,2);
55         mat.m[1][1]=mat.m[1][2]=mat.m[2][1]=1,mat.m[2][2]=0;
56         mat=matrix_pow(mat,n-1);
57         matrix ans(2,1);
58         ans.m[1][1]=b,ans.m[2][1]=a;
59         ans=multiply(mat,ans);
60         printf("%d\n",ans.m[1][1]);
61     }
62     return 0;
63 }