leetcode 263 Ugly Number

public class Solution {
    public boolean isUgly(int num) {
        if(num == 1)
            return true;
        if(num == 0)
            return false;
        if(num%2 == 0)
            return isUgly(num/2);
        if(num%3 == 0)
            return isUgly(num/3);
        if(num%5 == 0)
            return isUgly(num/5);
        return false;
    }
}

public boolean isUgly(int num) {
    if(num==1) return true;
    if(num==0) return false;
	while(num%2==0) num=num>>1;
	while(num%3==0) num=num/3;
	while(num%5==0) num=num/5;
    return num==1;
}

简单的说能用循环去解决的尽量去避免是用递归会好一些

num%2==0确实还可以写成n&1==0，但是为了可读性不做修改

leetcode 263 Ugly Number

原文：http://www.cnblogs.com/linkstar/p/5639226.html