hdu 1005

Problem Description

A number sequence is defined as follows:

f(1) = 1, f(2) = 1, f(n) = (A * f(n - 1) + B * f(n - 2)) mod 7.

Given A, B, and n, you are to calculate the value of f(n).

 

Input

The input consists of multiple test cases. Each test case contains 3 integers A, B and n on a single line (1 <= A, B <= 1000, 1 <= n <= 100,000,000). Three zeros signal the end of input and this test case is not to be processed.

Output

For each test case, print the value of f(n) on a single line.

 

Sample Input

1 1 31 2 100 0 0

 

Sample Output

25

 

Author

CHEN, Shunbao

 

Source

ZJCPC2004

代码： 

//number sequence#include<iostream>using namespace std;/*double f(int n){   //int x,y;   if(n==1||n==2)    return 1;   else      }}*/int main(){ int a,b,n; while(cin>>a>>b>>n&&(a&&b&&n)){int str[2]={1,1};for(int i=0;i<(n%49-1)/2;i++){str[0]=(a*str[1]+b*str[0])%7;str[1]=(a*str[0]+b*str[1])%7;}if(n%2)cout<<str[0]<<endl;elsecout<<str[1]<<endl; } return 0;}