263. The number of ugly
Write a program to determine whether a given number is a number of ugly.
Ugly contains only the number of prime factors is a positive integer of 2, 3, 5.
Example 1:
Input: 6
Output: true
interpretation: 6 = 2 × 3
Example 2:
Input: 8
Output: true
interpretation: 8 = 2 × 2 × 2
Example 3:
Input: 14
Output: false
explanation: the number 14 is not ugly, because it contains another prime factor 7.
Description:
1 is the number of ugly.
Does not exceed the range of the input 32-bit signed integers: [-231 231--1].
class Solution {
public boolean isUgly(int num) {
if (num<1) return false;
while (num%5==0){
num/=5;
}
while (num%3==0){
num/=3;
}
while (num%2==0){
num>>=1;
}
return num == 1;
}
}
