p263

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LeetCode p263 Ugly Number 题解

1.题目：

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. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.
Note that 1 is typically treated as an ugly number.

题意：

判断一个数是否为UglyNumber,即他的因数是否只有2，3，5.

2.解题思路:

见代码

3.代码

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public class Solution {
    public boolean isUgly(int num) {
        int[] a = { 2, 3, 5 };
		if (num == 1)
			return true;
		if (num == 0)
			return false;
		for (int i = 0; i < 3; i++) {
			while (num % a[i] == 0) {
				num = num / a[i];
				if (num == 1)
					return true;
			}
		}

		return false;
    }
}

4.一些总结：