hduoj #1005.Number Sequence

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=1005

Number Sequence

Time Limit:	2000/1000 MS (Java/Others)
Memory Limit:	65536/32768 K (Java/Others)

---

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

---

解题思路：总结规律
C语言代码如下

#include
int main()
{
    int a[100];
    int A,B,n;
    a[0] = 1;
    a[1] = 1;
    while(scanf("%d %d %d", &A, &B, &n) && A+B+n)
    {
        for(int i=2; i<50; i++)
            a[i] = (A*a[i-1] + B*a[i-2])%7;
        printf("%d\n", a[(n-1)%49]);
    }
    return 0;
}