LeetCode 263. Ugly Number
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.
Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.
Seen this question in a real interview before?
Yes
No
判断一个数是否是丑数,算法不难,但是要注意对0的讨论要放在最前面
代码如下:
1 class Solution { 2 public: 3 bool isUgly(int num) { 4 if (num == 0) 5 return false; 6 while (num % 2 == 0) 7 num /= 2; 8 while (num % 3 == 0) 9 num /= 3; 10 while (num % 5 == 0) 11 num /= 5; 12 return num == 1; 13 } 14 };