Write a program to check whether a given number is an ugly number.javascript
Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.java
Note that 1 is typically treated as an ugly number.spa
思路：判斷一個數是否爲「ugly number」，只須要判斷該數可否有限次的被2，3，5整除，且1也爲「ugly number」，即最後只要最後的結果爲1即爲「ugly number」。
code
language-javascriptorm
/**
* @param {number} num
* @return {boolean}
*/
var isUgly = function(num) {
if(num <= 0){
return false
}
if(num == 1){
return true;
}
while(num % 2 === 0){
num/=2;
}
while(num % 3 === 0){
num/=3;
}
while(num % 5 === 0){
num/=5;
}
return (num == 1)? true : false;
};