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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.
可以用循环,也可以用递归。
class Solution { public: bool isUgly(int num) { if (num <= 0) return false; if (num == 1) return true; 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; } };
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原文地址:http://www.cnblogs.com/Doctengineer/p/5859516.html