Submission #1176144

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Source Code Expand

N=int(input())
x=[int(i) for i in input().split()]
ans=1
index=0
advance=0
devide=10**9+7

while True:
	if 2*(index-advance)+1 <= x[index]:
		index+=1
		if index==N:
			break
	else:
		ans*=(index-advance+1)#need concern
		ans%=devide
		index+=1
		advance+=1
		if index==N:
			break
for i in range(index-advance,0,-1):
	ans*=i
	ans%=devide
print(ans)

Submission Info

Judge Result