leetcode 263. 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 prime factor 7.
Note:
1 is typically treated as an ugly number.
Input is within the 32-bit signed integer range: [−231,231 − 1].
class Solution {
public boolean isUgly(int num) {
if(num == 1) return true;
if(num == 0) return false;
int a = 2;
while(a != 0 && num % a == 0){
a = a * 2;
}
a = a /2 ;
if(a != 0)
num = num / a;
a =3;
while(a != 0 && num % a == 0){
a = a * 3;
}
a = a /3;
// System.out.println(b);
if(a != 0)
num = num / a;
a = 5;
while(a != 0 && num % a == 0){
a = a * 5;
}
a = a /5;
if(a != 0)
num = num / a;
if(num == 1) return true;
else
return false;
}
}
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