263. Ugly Number

原创于 2017-07-22 08:56:32 发布 · 220 阅读

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本文介绍了一种使用C++编程语言来判断一个给定的正整数是否为丑数的方法。丑数定义为仅包含质因数2、3和5的正整数。通过迭代去除这些质因数直至不能整除，最终判断剩余部分是否为1来确定该数是否为丑数。

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题目来源【Leetcode】

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.

用每个因子去除，看能否除尽：

class Solution {
public:
    bool isUgly(int num) {
    if(num < 1) return false;
    for (int i=2; i < 6; i++){
       while (num % i == 0)
          num = num/i;
    }
    return num == 1;
    }
};