杭电ACM1005

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<string.h>
int main()
{
int n;
int a, b;
while (scanf("%d%d%d", &a, &b, &n) != -1)
{
if (a == 0 && b == 0 && n == 0) break;
if (n == 1 || n == 2) {
printf("1\n");
continue;//之前这里是break，导致多次提交不成功
}
//int x = 1, y = 1, z;
int period, f[100] = {1,1};
for (int i = 2; i < 100; i++)
f[i] = (a*f[i - 1] + b*f[i - 2]) % 7;
int flag = 0;
int i, j;
for (i = 0; i < 49; i++)
{
for (j = i+1; j <= i+50; j++)
{
if (f[i] == f[j] && f[i + 1] == f[j + 1]){
flag = 1; break;
}
}
if (flag) break;
}
period = j - i;
//printf("j:%d i:%d\n", j, i);
//printf("period:%d\n", period);
n -= 1;
if (n <= i) printf("%d\n", f
);
else{
n -= i;
//printf("index:%d\n", n % period + i);
printf("%d\n", f[n % period + i]);
}
}
return 0;
}