题目链接
思路:
假设a是横着对折的次数,b是竖着对折的次数,则最终纸片数为(2a+1)*(2b+1)
代码:
#include<bits/stdc++.h>
#define int long long
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int N=6e6+10;
const int M=2e4+5;
const double eps=1e-8;
const int mod=998244353;
const int inf=0x7fffffff;
const double pi=3.1415926;
using namespace std;
int qpow(int a,int b)
{
int res=1;
while(b)
{
if(b&1)
res=res*a%mod;
a=a*a%mod;
b>>=1;
}
return res;
}
signed main()
{
int t;
cin>>t;
while(t--)
{
int n;
cin>>n;
int a=qpow(2,n)+1;
a%=mod;
int b=2*qpow(3,n)%mod*qpow(qpow(2,n),mod-2)%mod;
cout<<(a+b)%mod<<endl;
}
return 0;
}