Ugly Number Problem
Description
LeetCode Problem 263.
An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.
Given an integer n, return true if n is an ugly number.
Example 1:
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Input: n = 6
Output: true
Explanation: 6 = 2 × 3
Example 2:
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Input: n = 8
Output: true
Explanation: 8 = 2 × 2 × 2
Example 3:
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Input: n = 14
Output: false
Explanation: 14 is not ugly since it includes the prime factor 7.
Example 4:
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Input: n = 1
Output: true
Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.
Constraints:
- -2^31 <= n <= 2^31 - 1
Sample C++ Code
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class Solution {
public:
bool isUgly(int num) {
if (num == 1)
return true;
if (num <= 0)
return false;
while (num > 1) {
if (num % 2 == 0)
num /= 2;
else if (num % 3 == 0)
num /= 3;
else if (num % 5 == 0)
num /= 5;
else
return false;
}
return true;
}
};