代码

#pragma GCC optimize("Ofast,inline,fast-math,no-stack-protector,unroll-loops")
#include<bits/stdc++.h>
#define mod 1000000007
#define int long long
#define rep(i,a,b) for(int i(a);i<=(b);++i)
#define req(i,a,b) for(int i(a);i>=(b);--i)
using namespace std;
int ans;
int qpow(int x,int y)
{
	if(y==1)return x;if(!y)return 1;
	int res=qpow(x,y>>1);
	return (y&1)?res*res%mod*x%mod:res*res%mod;
}
signed main()
{
	int n,m;cin>>n>>m;
	if(n>m)swap(n,m);
	if(n==1) ans=qpow(2,m);
	else if(n==2) ans=qpow(3,m-1)*4%mod;
	else if(n==3) ans=qpow(3,m-3)*112%mod;
	else if(n==m) ans=(qpow(8,n)*83%mod+qpow(2,n+7)*5)%mod*190104168%mod;
	else ans=(qpow(8,n)*83%mod+qpow(2,n+8))%mod*qpow(3,-1+m-n)%mod*570312504%mod;
	cout<<ans;
	return 0;
}

评测结果