263. Ugly Number

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https://github.com/openset/leetcode/tree/master/problems/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.

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 pime factor 7.

Note:

  1. 1 is typically treated as an ugly number.
  2. Input is within the 32-bit signed integer range: [−231,  231 − 1]
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Time - log 2 N + log 3 N + log 5 N
Space - O(1)
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