README_EN.md

263. Ugly Number

中文文档

Description

An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.

Given an integer n, return true if n is an ugly number.

 

Example 1:

Input: n = 6
Output: true
Explanation: 6 = 2 × 3

Example 2:

Input: n = 1
Output: true
Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.

Example 3:

Input: n = 14
Output: false
Explanation: 14 is not ugly since it includes the prime factor 7.

 

Constraints:

• -231 <= n <= 231 - 1

Solutions

Python3

class Solution:
    def isUgly(self, n: int) -> bool:
        if n < 1:
            return False
        for x in [2, 3, 5]:
            while n % x == 0:
                n //= x
        return n == 1

Java

class Solution {
    public boolean isUgly(int n) {
        if (n < 1) return false;
        while (n % 2 == 0) {
            n /= 2;
        }
        while (n % 3 == 0) {
            n /= 3;
        }
        while (n % 5 == 0) {
            n /= 5;
        }
        return n == 1;
    }
}

C++

class Solution {
public:
    bool isUgly(int n) {
        if (n < 1) return false;
        while (n % 2 == 0) {
            n /= 2;
        }
        while (n % 3 == 0) {
            n /= 3;
        }
        while (n % 5 == 0) {
            n /= 5;
        }
        return n == 1;
    }
};

JavaScript

/**
 * @param {number} n
 * @return {boolean}
 */
var isUgly = function (n) {
    if (n < 1) return false;
    while (n % 2 == 0) {
        n /= 2;
    }
    while (n % 3 == 0) {
        n /= 3;
    }
    while (n % 5 == 0) {
        n /= 5;
    }
    return n == 1;
};

Go

func isUgly(n int) bool {
	if n < 1 {
		return false
	}
	for _, x := range []int{2, 3, 5} {
		for n%x == 0 {
			n /= x
		}
	}
	return n == 1
}

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