（HDOJ 1005）Number Sequence

Number Sequence

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 3 1 2 10 0 0 0

 

Sample Output

2 5

 

Author

CHEN, Shunbao

 

Source

ZJCPC2004

 

AC code:

#include <stdio.h>
#include<math.h>
int main()
{
    int a,b,i;
    long n,num[50];
    num[1]=num[2]=1;
    while(scanf("%d %d %ld",&a,&b,&n),a+b+n)
    {
     for(i=3;i<=48;i++)
     num[i%48]=(a*num[i-1]+b*num[i-2])%7;
     printf("%ld\n",num[n%48]);
    }
    return 0;

}