Luogu2290 [HNOI2004]树的计数 （组合计数，prufer编码）

这不prufer编码吗，防爆long long就行了啊

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)
#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)
#define Max(a,b) ((a) > (b) ? (a) : (b))
#define Min(a,b) ((a) < (b) ? (a) : (b))
#define Fill(a,b) memset(a, b, sizeof(a))
#define Abs(a) ((a) < 0 ? -(a) : (a))
#define Swap(a,b) a^=b^=a^=b
#define ll long long

#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("

----------

")
#define D_e(x)  cout << #x << " = " << x << endl
#define Pause() system("pause")
#define FileOpen() freopen("in.txt","r",stdin);

#else

#define D_e_Line ;
#define D_e(x)  ;
#define Pause() ;
#define FileOpen() ;

#endif

struct ios{
    template<typename ATP>ios& operator >> (ATP &x){
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;
        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();
        x*= f;
        return *this;
    }
}io;
using namespace std;

const int N = 157;

#define int long long
int C[N][N];
inline void Prepare(int &n){
	R(i,0,n){
		C[i][0] = 1;
		R(j,1,i){
			C[i][j] = C[i - 1][j - 1] + C[i - 1][j];
		}
	}
}
int d[N];
#undef int
int main(){
#define int long long
	int n;
	io >> n;
	int sum = 0;
	if(n == 1){
		io >> d[1];
		if(!d[1]){
			printf("1");
		}
		else{
			printf("0");
		}
		return 0;
	}
	R(i,1,n){
		io >> d[i];
		if(!d[i]){
			printf("0");
			return 0;
		}
		--d[i];
		sum += d[i];
	}
	
	if(sum != n - 2){
		printf("0");
		return 0;
	}
	
	Prepare(n);
	
	sum = 0;
	int ans = 1;
	R(i,1,n){
		ans *= C[n - 2 - sum][d[i]];
		sum += d[i];
	}
	
	printf("%lld", ans);
	
	return 0;
}