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
Submission
#include <iostream>
int A,B;
int f(int n){
if( n == 1 || n == 2){
return 1;
}
return (A*f(n-1)+B*f(n-2))%7;
}
int main(){
int n;
while(scanf("%d%d%d",&A,&B,&n)!=EOF,A||B||n){
int a = f(n%49);
printf("%d\n",a);
}
}