Codeforces Round #257 (Div. 2) B Jzzhu and Sequences

最新推荐文章于 2025-03-11 02:29:13 发布

Sunmh_AC

最新推荐文章于 2025-03-11 02:29:13 发布

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分类专栏：比赛找规律

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本文介绍了一种特殊序列的计算方法，通过分析序列的周期性质，实现快速计算任意项的值，并确保结果符合指定模数条件。适用于处理大规模数据输入的情况。

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Description

Jzzhu has invented a kind of sequences, they meet the following property:

$\text{[math]}$

You are given x and y, please calculate f_n modulo1000000007(10⁹ + 7).

Input

The first line contains two integers x andy(|x|, |y| ≤ 10⁹). The second line contains a single integern(1 ≤ n ≤ 2·10⁹).

Output

Output a single integer representing f_n modulo1000000007(10⁹ + 7).

Sample Input

Input

2 3
3

Output

Input

0 -1
2

Output

1000000006

Hint

In the first sample, f₂ = f₁ + f₃,3 = 2 + f₃,f₃ = 1.

In the second sample, f₂ = - 1; - 1 modulo (10⁹ + 7) equals(10⁹ + 6).

找规律

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>

using namespace std;

int main()
{
int n,m,k;
long long a[100];
while(~scanf("%d%d",&n,&m))
{
a[1]=n;
a[2]=m;
a[3]=m-n;
a[4]=-n;
a[5]=-m;
a[0]=n-m;
cin>>k;
k=k%6;
while(a[k]<0)
{
a[k]=1000000007+a[k];
}

printf("%lld\n",a[k]%1000000007);

}
return 0;
}