小南解题---蓝桥杯算法提高VIP-素数求和--while和for对比

'''zgn946

23:53 2022/5/11'''

#法一1372ms

a=int(input())

n=a

ls=[True]*(n+1)

s=0

for i in  range(2,n+1):

    if ls[i]:

        s+=i

        for  j in range(i*i,n+1,i):

            ls[j]=False

print(s)

'''

#法二658ms,while循环比for快

def scre_prime(n):

        re=[]

        primes=[True for i in range(n+1)]

        p=2

        while p*p<=n:

                if primes[p]:

                        for i in range(p*2,n+1,p):

                                primes[i]=False

                p+=1

        for i in range(2,n+1):

                if primes[i]:

                        re.append(i)

        return re

n=int(input())

a=scre_prime(n)

print(sum(a))

'''