poj 3070 Fibonacci 【矩阵乘法】

http://poj.org/problem?id=3070

题目大意：用矩阵乘法求Fibonacci数列

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <cmath>
#include <queue>
using namespace std;
template <class T> void checkmin(T &t,T x) {if(x < t) t = x;}
template <class T> void checkmax(T &t,T x) {if(x > t) t = x;}
template <class T> void _checkmin(T &t,T x) {if(t==-1) t = x; if(x < t) t = x;}
template <class T> void _checkmax(T &t,T x) {if(t==-1) t = x; if(x > t) t = x;}
typedef pair <int,int> PII;
typedef pair <double,double> PDD;
typedef long long ll;
#define foreach(it,v) for(__typeof((v).begin()) it = (v).begin(); it != (v).end ; it ++)
const int N = 2;
int n , MOD;
struct Matrix {
    int n , m;
    int a[N][N];
    Matrix() {}
    Matrix(int _n,int _m):n(_n),m(_m){};
    void intput() {
        for(int i=0;i<n;i++)
        for(int j=0;j<m;j++)
            scanf("%d",&a[i][j]);
    }
    Matrix operator + (const Matrix &b) {
        Matrix tmp = Matrix(n,m);
        for(int i=0;i<n;i++)
        for(int j=0;j<m;j++)
            tmp.a[i][j] = a[i][j] + b.a[i][j];
        return tmp;
    }
    Matrix operator - (const Matrix &b) {
        Matrix tmp = Matrix(n,m);
        for(int i=0;i<n;i++)
        for(int j=0;j<m;j++)
            tmp.a[i][j] = a[i][j] - b.a[i][j];
        return tmp;
    }
    Matrix operator * (const Matrix &b) {
        Matrix tmp = Matrix(n,b.m);
        for(int i=0;i<n;i++)
        for(int j=0;j<b.m;j++)
            tmp.a[i][j] = 0;
        for(int i=0;i<n;i++)
        for(int j=0;j<b.m;j++)
        for(int k=0;k<m;k++) {
            tmp.a[i][j] += a[i][k]*b.a[k][j];
            tmp.a[i][j] %= MOD;
        }
        return tmp;
    }
};

Matrix operator ^ (Matrix a , int p) {
    Matrix ret = Matrix(a.n,a.m);
    for(int i=0;i<a.n;i++)
    for(int j=0;j<a.m;j++)
        ret.a[i][j] = (i == j ? 1 : 0);
    while(p) {
        if(p%2) ret = ret * a;
        a = a * a;
        p /= 2;
    }
    return ret;
}
/*
Matrix mi(Matrix a , int p) {
    Matrix tmp = Matrix(a.n,a.m);
    for(int i=0;i<a.n;i++)
    for(int j=0;j<a.m;j++)
        if(i==j) tmp.a[i][j]=1;
        else tmp.a[i][j]=0;
    if(p == 0) return tmp;
    if(p == 1) return a;
    if(p % 2) tmp = a;
    Matrix tt = mi(a , p/2);
    return tt * tt * tmp;
}*/
Matrix A;
int main() {
    MOD = 10000;
    while(~scanf("%d",&n) && n != -1) {
        A = Matrix(2,2);
        A.a[0][0] = A.a[0][1] = A.a[1][0] = 1;
        A.a[1][1] = 0;
        //A = mi(A,n);
        A = A^n;
        printf("%d\n" , A.a[1][0]);
        /*
        cout << "n is "<<nn <<endl;
        cout << "check" << endl;
        for(int i=0;i<A.n;i++) {
            for(int j=0;j<A.m;j++) cout << A.a[i][j] << " ";
            cout << endl;
        }
        */
    }
    return 0;
}