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
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Example 2:
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| Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
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Example 3:
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| Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.
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Note:
1 is typically treated as an ugly number.- Input is within the 32-bit signed integer range: [−231, 231 − 1].
模拟
直接按照题意判断即可. 注意小于等于1的数的判断
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| class Solution {
public boolean isUgly(int num) {
if(num <= 0)
return false;
if(num == 1)
return true;
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;
}
}
|