FactorialQuery

#include <iostream>
#include <algorithm>
#define M 1000000007
#define N 1000001
using namespace std;
int v[N];

#define DIM 10000
char buff[DIM];
int poz=0;

void citeste(int &numar)
{
     numar = 0;
     //cat timp caracterul din buffer nu e cifra ignor
     while (buff[poz] < '0' || buff[poz] > '9')
          //daca am "golit" bufferul atunci il umplu
          if (++poz == DIM)
               fread(buff,1,DIM,stdin),poz=0;
     //cat timp dau de o cifra recalculez numarul
     while ('0'<=buff[poz] && buff[poz]<='9')
     {
          numar = numar*10 + buff[poz] - '0';
          if (++poz == DIM)
               fread(buff,1,DIM,stdin),poz=0;
     }
}

int main()
{
    int n;
    cin>>n;
    for(int i=0;i<n;++i)
        citeste(v[i]);
    sort(v,v+n);
    int fact=1;
    for(int i=1;i<=v[0];++i)
        fact=(int)(1LL*fact*i%M);
    int p=fact;
    for(int i=1;i<n;++i)
    {
        if(v[i]==v[i-1])
            p=(int)(1LL*p*fact%M);
        else
        {
            for(int j=v[i-1]+1;j<=v[i];++j)
                fact=(int)(1LL*fact*j%M);
            p=(int)(1LL*p*fact%M);
        }
    }
    cout<<p<<'\n';
    return 0;
}