如下是我的代码，本机样例都过不去就鬼畜报错，一交100pts，十分莫名其妙，Orz_stO求大佬释疑。

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,m,T,mod;
int qp(int n,int p,int mod){
	if(p==0)return 1;
	if(p==1)return n;
	if(p%2==0)return qp(n*n%mod,p/2,mod)%mod;
	return n*qp(n*n%mod,p/2,mod)%mod;
}
int exgcd(int a,int b,int &x,int &y){
	if(b==0){
		x=1;y=0;return a;
	}
	
	int res=exgcd(b,a%b,y,x);
	y-=a/b*x;
	return res;
}
int inv(int n,int p,int mod){
	int xx,yy;
	exgcd(n,p,xx,yy);
	xx=(xx%mod+mod)%mod;
	return xx;
}
int cnt(int n,int p,int k){
	if(n==0)return 1;
	int ans=1,a2=1;
	for(int i=1;i<k;i++){
		if(i%p!=0)ans=ans*i%k;
	}
	ans=qp(ans,n/k,k)%k;
		for(int i=k*(n/k);i<=n;i++){
		if(i%p!=0)a2=a2*(i%k)%k;
	}
	return ans%k*a2%k*cnt(n/p,p,k)%k;
}
int C1(int n,int m,int p,int k){
	if(n<m)return 0;
	int f1=cnt(n,p,k),f2=cnt(m,p,k),f3=cnt(n-m,p,k),c=0;
	for(int i=m;i>0;i/=p)c-=i/p;
	
	for(int i=n;i>0;i/=p)c+=i/p;
	for(int i=n-m;i>0;i/=p)c-=i/p;
	return f1*inv(f2,k,k)%k*inv(f3,k,k)%k*qp(p,c,k)%k;
}
int CRT(int a[],int t[],int m[],int n,int mod){
	int res=0;
	for(int i=1;i<=n;i++)res=(res+a[i]%mod*t[i]%mod*m[i]%mod)%mod;
	return res;
}
int C(int n,int m,int mod){
	int a[100005],pk[100005],mi[100005];
	int n2=mod,point=1;
	for(int i=2;i<=sqrt(mod)&&n2;i++){
		int tmp=1;
		while(n2%i==0){
			n2/=i;
			tmp*=i;
		}
		if(tmp>1){
			a[point]=C1(n,m,i,tmp);
			pk[point]=tmp;
		point++;
		}
	}
	if(n2>1){
		a[point]=C1(n,m,n2,n2);
		pk[point]=n2;
		point++;
	}
	for(int i=1;i<point;i++)mi[i]=inv((mod/pk[i])%pk[i],pk[i],pk[i])%pk[i];
	for(int i=1;i<point;i++)pk[i]=mod/pk[i];
	return CRT(a,pk,mi,point-1,mod);
}
int a[100005],ans=1;
signed main(){
	cin>>mod;
	cin>>n>>m;
	int sum=0;
	for(int i=1;i<=m;i++){
		cin>>a[i];
		if(n<a[i]){
			cout<<"Impossible\n";
			exit(0);
		}
		ans=(ans*C(n,a[i],mod))%mod;
		n-=a[i];
		
	}
	cout<<ans;
}