杭电acm 1005

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

递归做的话会  Runtime Error (STACK_OVERFLOW)

#include

#include
int fac(int a,int b,int n)
{
if(n==1||n==2)
return 1;
else return (a*fac(a,b,n-1)+b*fac(a,b,n-2))%7;
}
int main(int argc, char *argv[])
{
int a,b,n;
int m;
while(scanf("%d%d%d",&a,&b,&n)!=EOF)
{
if(a==0&&b==0&&n==0)
break;
m=fac(a,b,n);
printf("%d\n",m);
}


return 0;
}

附上AC答案

#include
int  main()
{
    int  a,b;
    long  n;
    int  f[201];
    int  i;
    while ( scanf ( "%d%d%ld" ,&a,&b,&n)!=EOF)
    {
        if (n==0&&a==0&&b==0)
            break ;
        f[1]=1;
        f[2]=1;
        if  (n>=3)
        {
            for (i=3;i<200;i++)
            {
                f[i]=(a*f[i-1]+b*f[i-2])%7;
                if  ((f[i-1]==1)&&(f[i]==1))
                {
                    break ;
                }
            }
            i=i-2;
            n%=i;
            if  (n==0)
            {
                n=i;
            }
            printf ( "%d\n" ,f[n]);
        }
        else
        {
            printf ( "1\n" );
        }
    }
    return  0;
}

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

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