Question

我正在进行pyschools练习，我在主题5问题12 - Prime Factorization中遇到问题，我必须这样做：

给定一个正整数，写一个函数来计算可以多次一起运算的素数因子，以获得相同的整数。

Examples

  >>> primeFactorization(60)
  [2, 2, 3, 5]
  >>> primeFactorization(1050)
  [2, 3, 5, 5, 7]
  >>> primeFactorization(1)
  []

这是我的代码：

import operator
import functools as fun

def primeFactorization(num): 
    num = num
    primes = []
    result = []
    if num > 1:
        [primes.append(x) for x in range(2, num) if all(x % y != 0 for y in range(2, x))]
    multy = fun.reduce(operator.mul, result, 1)
    for number in primes:
        if num % number == 0 and multy != num:
            result.append(number)
    return result

这让我回答：

Test Cases              Expected Result    Returned Result
primeFactorization(33)  [3, 11]            [3, 11]  
primeFactorization(84)  [2, 2, 3, 7]       [2, 3, 7]    
primeFactorization(1)   []                 []

我试过这个并且我的私人测试用例失败了：

import operator
import functools as fun

def primeFactorization(num): 
    num = num
    primes = []
    result = []
    if num > 1:
        [primes.append(x) for x in range(2, num) if all(x % y != 0 for y in range(2, x))]
    multy = fun.reduce(operator.mul, result, 1)
    for number in primes:
        if num % number == 0:
            result.append(number)

    multy = fun.reduce(operator.mul, result, 1)
    y = num/multy
    if y != 1 and y in primes:
        result.insert(0, int(y))
    return result

Test Cases              Expected Result Returned Result
primeFactorization(33)  [3, 11]         [3, 11] 
primeFactorization(84)  [2, 2, 3, 7]    [2, 2, 3, 7]    
Private Test Cases      Passed          Failed  
primeFactorization(1)   []              []

我能做些什么来传递？

Answer 1

为什么要这么复杂？找到给定数字X的所有素因子的问题与找到我们可以将X分成的最小数字（大于1）的集合相同。要解决此问题，我们可以从查找除n的最小数字X开始。这是X的第一个主要因素。然后我们可以通过找到X/n

的素因子来找到其余的素因子

def primeFactorization(X):

    possible = [2] + range(3,int(ceil(sqrt(X)))+1,2)

    for p in possible:
        if X % p == 0:
            return [p] + primeFactorization(X/p)

    return [X]


primeFactorization(3*3*7*5*11*13*31)

> [3,3,5,7,11,13,31]

Pyschools Prime分解

1 个答案: