[LeetCode] 263. Ugly Number

原创于 2017-01-25 17:55:11 发布 · 363 阅读

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本文介绍了一个C++程序，用于判断一个给定的正整数是否为丑数。丑数是指仅包含质因数2、3和5的正整数。文章中的程序通过不断除以这些质因数来简化输入的数字，并最终确定该数字是否可以完全被分解为这些质因数。

原题地址

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.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

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/**
 * LeetCode 263 - Ugly Number
 * tangxijie
 * 2017-01-25
 */
class Solution {
public:
    bool isUgly(int num) {
    	if(num <= 0) 
    	{
    		return false;
    	}

    	while (num % 2 == 0) num /= 2;
    	while (num % 3 == 0) num /= 3;
    	while (num % 5 == 0) num /= 5;

    	if (num == 1)
    		return true;
    	else
    		return false;        
    }
};