nefu 115 斐波那契的整除

题目：http://acm.nefu.edu.cn/test/problemshow.php?problem_id=115

题意：水

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;
int main()
{
    long long n;
    while(scanf("%lld",&n)!=EOF)
    {
        if(n%12==0)
            cout<<"YES\n";
        else if(n%6==0)
            cout<<4<<endl;
        else if(n%4==0)
            cout<<3<<endl;
        else
            cout<<"NO\n";
    }
    return 0;
}

或者下面代码：

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;
#define mod 12
struct Matrix
{
    int m[3][3];
}E,D;
void init()
{
    for(int i=1;i<=2;i++)
        for(int j=1;j<=2;j++)
        {
            E.m[i][j]=(i==j);
            D.m[i][j]=1;
        }
    D.m[2][2]=0;
}
Matrix multi(Matrix A,Matrix B)
{
    Matrix ans;
    for(int i=1;i<=2;i++)
        for(int j=1;j<=2;j++)
        {
            ans.m[i][j]=0;
            for(int k=1;k<=2;k++)
                ans.m[i][j]=(ans.m[i][j]+A.m[i][k]*B.m[k][j])%mod;
        }
    return ans;
}
Matrix Pow(Matrix A,long long k)
{
    Matrix ans=E;
    while(k)
    {
        if(k&1)
        {
            k--;
            ans=multi(A,ans);
        }
        else
        {
            k/=2;
            A=multi(A,A);
        }
    }
    return ans;
}
void Print(Matrix A)
{
    for(int i=1;i<=2;i++)
    {
        for(int j=1;j<=2;j++)
            cout<<A.m[i][j]<<" ";
        cout<<endl;
    }
}
int main()
{
    long long n;
    init();
    while(scanf("%lld",&n)!=EOF)
    {
        Matrix ans=Pow(D,n);
        if(ans.m[1][2]%12==0)
            cout<<"YES\n";
        else if(ans.m[1][2]%3==0)
            cout<<3<<endl;
        else if(ans.m[1][2]%4==0)
            cout<<4<<endl;
        else
            cout<<"NO\n";
    }
    return 0;
}