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
由分析可知，结果只有7*7=49种情况，并且是循环往复的，所以采用以下算法~
代码：
import java.util.Scanner;
public class Main1005 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int a, b, n;
while (in.hasNext()) {
a = in.nextInt();
b = in.nextInt();
n = in.nextInt();
if (a == 0 & b == 0 & n == 0)
System.exit(0);
int f[] = new int[50];
for (int i = 1; i < 50; i++) {
if (i == 1 || i == 2) {
f[i] = 1;
} else {
f[i] = (a * f[i - 1] + b * f[i - 2]) % 7;
}
}
System.out.println(f[n % 49]);
}
}
}
