Ugly Number

Desicription

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:

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Input: 6
Output: true
Explanation: 6 = 2 × 3

Example 2:

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Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2

Example 3:

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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].

Solution

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class Solution {
private:
public:
bool isUgly(int num) {
if(!num) {
return false;
}
while(!(num % 2)) {
num /= 2;
}
while(!(num % 3)) {
num /= 3;
}
while(!(num % 5)) {
num /= 5;
}
return num == 1;
}
};