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. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.
Note that 1 is typically treated as an ugly number. 解讀 給定一個數，判斷該數字是否是ugly，ugly number的定義是：該數字的素因數（就是那種身上沒有一點肉了，再瘦不下來了的數字）如果是【2,3,5】之外的數字，那么不是ugly，否則是ugly，比如14的素因數有2,7，那么就不是ugly了，12的素因數是：2,3，就是ugly啦
或者簡寫成這樣的
class Solution(object): def isUgly(self, num): for p in 2, 3, 5: while num % p == 0 < num: num /= p return num == 1再來一個遞歸版本的,這個效率達到了這里面的最高92.03%
#1.如果這個數小于1，返回，否#2.讓該數依次對【2,3,5】取余數#如果為0，把該數重新賦值，遞歸回去class Solution(object): def isUgly(self, num): if (num <= 0):return False; if (num == 1):return True; if num%2==0: return self.isUgly(num/2) if num%3==0: return self.isUgly(num/3) if num%5==0: return self.isUgly(num/5) return False新聞熱點
疑難解答
