POJ 3070 Fibonacci 矩阵快速幂

#include <cstdio>
#include <iostream>
#include <cstring>
#define sf scanf
#define pf printf
using namespace std;
const int maxn = 10;

struct Matrix{
int C[maxn][maxn];
int n;
};
Matrix operator*(const Matrix& a,const Matrix& b){
Matrix ret;
memset(ret.C,0,sizeof(ret.C));
ret.n = a.n;
for(int i =1;i <= a.n;++i){
for(int j = 1;j <= a.n;++j){
for(int k = 1;k <= a.n;++k){
ret.C[i][j] += a.C[i][k] * b.C[k][j];
ret.C[i][j] %= 10000;
}
}
}
return ret;
}
Matrix operator^(Matrix a,int n){
Matrix ret;
ret.n = a.n;
for(int i = 0;i <= ret.n;++i){
for(int j = 0;j <= ret.n;++j){
ret.C[i][j] = (i == j);
}
}
while(n){
if(n&1) ret = ret * a,n--;
a = a * a;
n >>= 1;
}
return ret;
}

int main(){
int n;
while( sf("%d",&n) && ~n ){
Matrix ret;
ret.n = 2;
ret.C[1][1] = 1;
ret.C[1][2] = 1;
ret.C[2][1] = 1;
ret.C[2][2] = 0;
ret = ret ^ n;
pf("%d\n",ret.C[1][2]);
}
return 0;
}