How Many Sets ITime Limit: 2 Seconds Memory Limit: 65536 KB
Give a set S, |S| =n, then how many ordered set group (S1, S2, ..., Sk) satisfies S1 ∩ S2 ∩ ... ∩ Sk= ∅. (Si is a subset of S, (1 <=i<=k))
Input
The input contains multiple cases, each case have 2 integers in one line representnandk(1 <=k<=n<= 231-1), proceed to the end of the file.
Output
Output the total number mod 1000000007.
Sample Input
1 12 2
Sample Output
19
整套比赛最简单的一个。
可以直接写一个暴力程序，然后找规律。
规律很显然的~
我的代码：
#include<stdio.h>#include<iostream>using namespace std;typedef long long ll;ll mod=1000000007;ll power(ll p,ll n,ll m){ll sq=1;while(n>0){if(n%2==1)sq=(sq%m)*(p%m)%m;p=(p%m)*(p%m)%m;n=n/2;}return sq%m;}int main(){ll n,k,ans;while(cin>>n>>k){ans=power(2,k,mod)-1;ans=power(ans,n,mod);cout<<ans<<endl;}return 0;}
