Prufer编码的应用。懒的写质因数分解，直接高精度。

注意当n=1的特殊情况的处理。

#include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          #include 
          
           #include 
           
            #define rep(i, l, r) for(int i=l; i<=r; i++)#define down(i, l, r) for(int i=l; i>=r; i--)#define N 234#define Q 1000000using namespace std;int read(){ int x=0, f=1; char ch=getchar(); while (ch<'0' || ch>'9') { if (ch=='-') f=-1; ch=getchar(); } while (ch>='0' && ch<='9') { x=x*10+ch-'0'; ch=getchar(); } return x*f;}int n, d[N], m[N], l;void Mult(int x){ rep(i, 1, l) m[i]*=x; rep(i, 1, l) m[i+1]+=m[i]/Q, m[i]%=Q; while (m[l+1]) l++, m[l+1]+=m[l]/Q, m[l]%=Q;}void Div(int x){ int a=0; down(i, l, 1) a=a*Q+m[i], m[i]=a/x, a%=x; while (!m[l] && l>1) l--;}int main(){ n=read(); if (n==1) { int x=read(); if (!x) printf("1"); else printf("0"); return 0; } rep(i, 1, n) d[i]=read()-1; rep(i, 1, n) if (d[i]<0 || d[i]>n-2) { printf("0\n"); return 0; } int a=0; rep(i, 1, n) a+=d[i]; if (a != n-2) { printf("0\n"); return 0; } m[l=1]=1; rep(i, 1, n-2) Mult(i); rep(i, 1, n) rep(j, 1, d[i]) Div(j); printf("%d", m[l]); down(i, l-1, 1) if (m[i]>=100000) printf("%d", m[i]); else if (m[i]>=10000) printf("0%d", m[i]); else if (m[i]>=1000) printf("00%d", m[i]); else if (m[i]>=100) printf("000%d", m[i]); else if (m[i]>=10) printf("0000%d", m[i]); else printf("00000%d", m[i]); return 0;}