問14
def question14(n):
prime = []
is_prime = [True for _ in range(n + 1)]
is_prime[0] = False
is_prime[1] = False
for i in range(2, n + 1):
if is_prime[i]:
prime.append(i)
j = 2 * i
while j <= n:
is_prime[j] = False
j += i
return len(prime)
question14(10)
4
question14(100)
25
question14(1000)
168
question14(10000)
1229
question14(100000)
9592