LeetCode 263 Ugly Number

题目描述

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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代码

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