HDU 2256 Problem of Precision (矩阵快速幂)

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2256

最重要的是构建递推式，下面的图是盗来的。貌似这种叫共轭数。

 #include <iostream>
 #include <cstdio>
 #include <cmath>
 #include <cstring>
 #include <algorithm>
 using namespace std;
 const int mod = ;
 struct data {
     int mat[][];
     data() {}
     data(int x, int y, int z1 = , int z2 = ) {
         mat[][] = x, mat[][] = y;
         mat[][] = z1, mat[][] = z2;
     }
 };

 data operator* (data a, data b) {
     data ans;
     for(int i = ; i <= ; ++i) {
         for(int j = ; j <= ; ++j) {
             ans.mat[i][j] = ;
             for(int k = ; k <= ; ++k)
                 ans.mat[i][j] = (ans.mat[i][j] + a.mat[i][k] * b.mat[k][j] % mod) % mod;
         }
     }
     return ans;
 }

 data operator^ (data a, int n) {
     data ans;
     for(int i = ; i <= ; ++i) {
         for(int j = ; j <= ; ++j) {
             ans.mat[i][j] = (i == j);
         }
     }
     while(n) {
         if(n & )
             ans = ans * a;
         a = a * a;
         n >>= ;
     }
     return ans;
 }

 int main()
 {
     int t, n;
     scanf("%d", &t);
     while(t--) {
         scanf("%d", &n);
         data ans(, );
         data a(, , , );
         a = a ^ (n - );
         ans = ans * a;
         printf("%d\n", (ans.mat[][] *  -  + mod) % mod);
     }
     return ;
 }