HDOJ--1005--Number Sequence

題目描述：
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).
輸入描述:
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.
輸出描述:
For each test case, print the value of f(n) on a single line.
輸入：
1 1 3
1 2 10
0 0 0
輸出：
2
5
題意：
算題面公式
題解：
找規律
代碼：

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

int f[50];
int a,b,n;

void init(){
    f[1] = 1;
    f[2] = 1;
    for(int i = 3; i <= 48; i ++){
        f[i] = (a * f[i - 1] + b * f[i - 2])%7;
    }
}

int main(){
    while(scanf("%d%d%d",&a,&b,&n)!=EOF){
        if(a == 0 && b == 0 && n == 0) break;
        init();
        cout<<f[n%48]<<endl;
    }
    return 0;
}