hdu 5642 King's Order

http://acm.hdu.edu.cn/showproblem.php?pid=5642

 

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

int main()
{
    int n,t;
    long long a[4],ans,cut1,cut2;
    cin>>t;
    while (t--)
    {
        cin>>n;
        if (n<=0)
        {
            cout<<"0"<<endl;
            continue;
        }
        if (n==1)
        {
            cout<<"26"<<endl;
            continue;
        }
        a[0]=26*25;
        a[1]=26;
        a[2]=0;
        for (int i=3;i<=n;i++)
        {
            cut1=a[0];
            cut2=a[1];
            a[0]=((a[0]+a[1]+a[2])*25)%1000000007;
            a[1]=cut1;
            a[2]=cut2;

        }
        ans=(a[1]+a[2]+a[0])%1000000007;
        cout<<ans<<endl;
    }
    return 0;
}