Submission #994542

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Source Code Expand

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<cstdio>
#include<sstream>
#include<iomanip>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
using namespace std;
//kaewasuretyuui
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef pair<int,pii> pip;
typedef vector<pip>vip;
const double PI=acos(-1);
const double EPS=1e-8;
const int inf=1e8;
int main(){
	ll n,m;
	cin>>n>>m;
	if(n>m){
		cout<<0<<endl;
		return 0;
	}
	vi dp(n+2);
	dp[1]=1;
	ll MOD=1000000007;
	rep(i,m){
		vi ndp(n+2);
		rep(j,n+1){
			if(j!=n)(ndp[j+1]+=dp[j]*(n-j))%=MOD;
			(ndp[j]+=dp[j]*(j-(j==n?1:0)))%=MOD;
		}
		ndp[n+1]=(dp[n+1]*n+dp[n])%MOD;
		dp=ndp;
//		rep(j,n+2)cout<<" "<<dp[j];cout<<endl;
	}
	cout<<dp[n+1]<<endl;
}

Submission Info

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