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今天選了這題#Easy #Math的,Ugly Number,試著自己解這題

進入正題

Write a program to check whether a given number is an ugly number.
Ugly numbers are positive numbers whose prime factors only include 2, 3, 5.
Example 1:
Input: 6
Output: true
Explanation: 6 = 2 × 3
Example 2:
Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
Example 3:
Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.
Note:

1. 1 is typically treated as an ugly number.
2. Input is within the 32-bit signed integer range: [−2^31, 2^31 − 1].

這邊題目說了,Ugly Number就是由2或3或5為因數的正數數字,且1也是Ugly Number.
我想到的是先用排除的方法,把小於1的,除2或除3或除5不為0的數字排除,最後除完的數字為1的話就是true

def isUgly(self, num: int) -> bool:
    if num < 1:
        return False
    while num > 0:
        if num == 1:
            return True
        elif num % 2 == 0:
            num = num // 2
        elif num % 3 == 0:
            num = num // 3
        elif num % 5 == 0:
            num = num // 5
        else:
            return False

submit後結果如下:

參考資料