(HDOJ 1005)Number Sequence

Number Sequence
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
 

Source
 
AC code:

#include <stdio.h>
#include
<math.h>
int main()
{
    
int a,b,i;
    
long n,num[50];
    num[
1]=num[2]=1;
    
while(scanf("%d %d %ld",&a,&b,&n),a+b+n)
    {
     
for(i=3;i<=48;i++)
     num[i
%48]=(a*num[i-1]+b*num[i-2])%7;
     printf(
"%ld\n",num[n%48]);
    }
    
return 0;
} 

 

posted @ 2011-04-13 20:50  cpoint  阅读(383)  评论(0编辑  收藏  举报
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