defcountPrimes(self, n): ifn <3: return0 primes=[True]*n primes[0]=primes[1]=False foriinrange(2,int(n**0.5)+1): ifprimes[i]: primes[i*i: n: i]=[False]*len(primes[i*i: n: i]) returnsum(primes) 下面的code是有人针对上面这个code进行改进的code: 1 2 3 4 5 6 7 8 9...
primes = [True] * n primes[0] = primes[1] = False for i in range(2, int(n**0.5)+1): if primes[i]: for j in range(i*i, n, i): primes[j] = False return sum(primes)
代码: classSolution:defcountPrimes(self, n: int) ->int: count,flag= 0,[True]*(n)#1代表质数,0代表非质数foriinrange(2,n):#从2开始遍历,i代表当前第一个数,i代表这个数所在位置ifflag[i]:#如果当前位置判定为True的话count += 1forjinrange(i*i,n,i):#将该质数的所有倍数都设定为False,即...
Count Primes Problem: Count the number of prime numbers less than a non-negative number, n. 解释:计算小于n的所有质数。(质数定义为在大于1的自然数中,除了1和它本身以外不再有其他因数。) Solve: 逐一判断的方法会超时。这里用的是埃拉托斯特尼筛法。2是质数,那么 4,6,8,10...等都不是质数。3是...
Approach #3: Python. classSolution: defcountPrimes(self, n): """ :type n: int :rtype: int """ ifn <3: return0 primes = [True] * n primes[0] = primes[1] =False foriinrange(2, int(n**0.5)+1): ifprimes[i]: primes[i*i : n : i] = [False] * len(primes[i*i : ...
from itertools import count def is_prime(n): if n < 2: return False for i in range(2, int(n**0.5) + 1): if n % i == 0: return False return True def prime_generator(): for n in count(2): if is_prime(n): yield n # 使用素数迭代器生成前10个素数 primes = [] prime_it...
Approach #3: Python. class Solution: def countPrimes(self, n): """ :type n: int :rtype: int """ if n < 3: return 0 primes = [True] * n primes[0] = primes[1] = False for i in range(2, int(n**0.5)+1): if primes[i]: primes[i*i : n : i] = [False] * len(...
PRIMES = [112272535095293] * 100 def is_prime(n): if n < 2: return False if n == 2: return True if n % 2 == 0: return False sqrt_n = int(math.floor(math.sqrt(n))) for i in range(3, sqrt_n + 1, 2): if n % i == 0: ...
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primecount is a command-line program and C/C++ library that counts the number of primes ≤ x (maximum 1031) using highly optimized implementations of the combinatorial prime counting algorithms.primecount includes implementations of all important combinatorial prime counting algorithms known up to this...