（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 ;

}