n=int(input()) list1=list(map(int, input().split())) max1=max(list1) list1.sort() dic={} for i in list1: if i not in dic: dic[i]=1 else: dic[i]+=1 res=1 def c(a,b): res=1 for i in range(b): res*=(a-i)/(i+1) #如果b>a 则res为0 return res for i in range(1,max1+1): d=c(dic[i-1]*2,dic[i]) res*=d print(int(res)%1000000007) 我这种怎么才20%呀😂