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

#include<stdio.h>
#include<math.h>
int main()
{
    int a,b;
    long long n;
    long long c[1000];
    int d;
    while(scanf("%d %d %lld",&a,&b,&n)==3)
    {
        c[1]=1;
        c[2]=1;
        for(d=3;d<=n;d++)
        {
            c[d]=(b*c[1]+a*c[2]);
            c[1]=c[2];
            c[2]=c[d];
        }
        if(a==0&&b==0&&n==0)
        break;
        printf("%lld\n",c[2]%7);
    }
    return 0;
}

那要怎么修改呢？

谢谢 我得好好消化一下你的代码

设定大数组 比如long long a[]这样的 是不是不符合规定的？