Number Sequence 分类： HDU 2015-06-19 20:54 10人阅读 评论(0) 收藏

Number Sequence
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 124827 Accepted Submission(s): 30331

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
数据很大，所以肯定有循环节

#include <iostream>
#include <cstdio>
using namespace std;
int Arr[10000];
int main()
{
    int a,b,i;
    int  n;
    Arr[1]=1;
    Arr[2]=1;
    while(cin>>a>>b>>n)
    {
        if(!a&&!b&&!n)
        {
            break;
        }
        for( i=3; i<10000; i++)
        {
            Arr[i]=(a*Arr[i-1]+b*Arr[i-2])%7;
            if(Arr[i]==1&&Arr[i-1]==1)
            {
                break;
            }
        }
        n=n%(i-2);
        Arr[0]=Arr[i-2];
        cout<<Arr[n]<<endl;
    }
    return 0;

}

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