hdu 1005 数论 循环

Problem : 1005 ( Number Sequence )     Judge Status : Accepted
RunId : 9085676    Language : G++    Author : xiaoniuwin
Code Render Status : Rendered By HDOJ G++ Code Render Version 0.01 Beta

#include <iostream>
using namespace std;
int main()
{
    int a,b,n;
    int f[1005];
    while(cin>>a>>b>>n)
    {
        if(a==0&&b==0&&n==0)
            break;
        f[1]=1;
        f[2]=1;
        int i=3;
        for(i;i<1004;)
        {
            f[i]=(a*f[i-1]+b*f[i-2])%7;
            if(f[i]==1&&f[i-1]==1)
                break;
            i++;
        }
        i=i-2;
        n=n%i;
        if(n==0) cout<<f[i]<<endl;
        else
        cout<<f[n]<<endl;
    }
    return 0;
}