Prime number decompositions
Codewars Kata 47√
Description
https://www.codewars.com/kata/53c93982689f84e321000d62/solutions/python
-简述：本题给定一个数字，要求设计三个函数，分别求该数字的全部质因数、质因数以及其幂数、各质因数的乘积数组。
-思路：求出所有质因数，再按照要求的输出格式进行输出
-难点：1 避免time out的情况 2 避免步骤重复繁琐
You have to code a function getAllPrimeFactors which take an integer as parameter and return an array containing its prime decomposition by ascending factors, if a factors appears multiple time in the decomposition it should appear as many time in the array.
Exemple: getAllPrimeFactors(100) returns [2,2,5,5] in this order.
This decomposition may not be the most practical.
You should also write getUniquePrimeFactorsWithCount, a function which will return an array containing two arrays: one with prime numbers appearing in the decomposition and the other containing their respective power.
Exemple: getUniquePrimeFactorsWithCount(100) returns [[2,5],[2,2]]
You should also write getUniquePrimeFactorsWithProducts an array containing the prime factors to their respective powers.
Exemple: getUniquePrimeFactorsWithProducts(100) returns [4,25]
Errors, if:
n is not a number n not an integer n is negative or 0 The three functions should respectively return [], [[],[]] and [].
Edge cases:
if n=0, the function should respectively return [], [[],[]] and [].
if n=1, the function should respectively return [1], [[1],[1]], [1].
if n=2, the function should respectively return [2], [[2],[1]], [2].
The result for n=2 is normal. The result for n=1 is arbitrary and has been chosen to return a usefull result. The result for n=0 is also arbitrary but can not be chosen to be both usefull and intuitive. ([[0],[0]] would be meaningfull but wont work for general use of decomposition, [[0],[1]] would work but is not intuitive.)
My solution
import collections
def getAllPrimeFactors(n):
dec = []
i = 2
if str(n).isdigit():
if n == 1:
return [1]
else:
while n > 1:
while n % i == 0:
n /= i
dec.append(i)
i += 1
return dec
else:
return []
def getUniquePrimeFactorsWithCount(n):
c = collections.Counter(getAllPrimeFactors(n))
lst1 = []
lst2 = []
for key,value in c.items():
lst1.append(key)
lst2.append(value)
return [lst1,lst2]
def getUniquePrimeFactorsWithProducts(n):
c = getUniquePrimeFactorsWithCount(n)
return [c[0][i]**c[1][i] for i in range(0,len(c[0]))]
print(getUniquePrimeFactorsWithProducts(100))
Given solutions
import math
import collections
def getAllPrimeFactors(n):
numberToDecompose = n
if (not isinstance(numberToDecompose,(int,long)) or numberToDecompose<=0): return []
answer = ([1] if (numberToDecompose==1) else [])
for possibleFactor in range (2,numberToDecompose+1):
while (numberToDecompose % possibleFactor == 0):
answer.extend([possibleFactor])
numberToDecompose = numberToDecompose / possibleFactor
answer = sorted(answer)
return answer
def getUniquePrimeFactorsWithProducts(n):
ch= getUniquePrimeFactorsWithCount(n)
x= [a**b for (a,b) in zip (ch[0], ch[1])]
return x
def getUniquePrimeFactorsWithCount(n):
c = collections.Counter (getAllPrimeFactors(n))
d= [a for (a,_) in c.items()]
e = [b for (_,b) in c.items()]
return [d,e]
Points
1 collections.Counter 计数 生成字典形式
或者Counter()直接计数
2 报错TypeError: ‘builtin_function_or_method’ object is not subscriptable 错误原因：括号用错了 append后面应该是()
