【BZOJ4475】子集选取（计数）

题意：

思路：

 #include<cstdio>
 #include<cstdlib>
 #include<iostream>
 #include<algorithm>
 #include<cstring>
 #define MOD 1000000007
 typedef long long LL;
 using namespace std;
 LL n,k,ans;

 LL pow(LL x,LL y)
 {
     LL s=; LL t=x;
     while(y)
     {
         if(y&) s=s*t%MOD;
         t=t*t%MOD;
         y>>=;
     }
     return s;
 }

 int main()
 {
     freopen("bzoj4475.in","r",stdin);
     freopen("bzoj4475.out","w",stdout);
     scanf("%lld%lld",&n,&k);
     ans=pow(,n*k);
     printf("%lld\n",ans);
     return ;
 }