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➤微信公众号:山青咏芝(shanqingyongzhi)
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➤原文地址:https://www.cnblogs.com/strengthen/p/9751111.html
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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
.
Example 1:
Input: 6
Output: true
Explanation: 6 = 2 × 3
Example 2:
Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
Example 3:
Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7 .
Note:
-
is typically treated as an ugly number.1
- Input is within the 32-bit signed integer range: [−231, 231 − 1].
编写一个程序判断给定的数是否为丑数。
丑数就是只包含质因数
2, 3, 5
的正整数。
示例 1:
输入: 6
输出: true
解释: 6 = 2 × 3
示例 2:
输入: 8
输出: true
解释: 8 = 2 × 2 × 2
示例 3:
输入: 14
输出: false
解释: 14 不是丑数,因为它包含了另外一个质因数 7 。
说明:
-
是丑数。1
- 输入不会超过 32 位有符号整数的范围: [−231, 231 − 1]。
20ms
1 class Solution {
2 func isUgly(_ num: Int) -> Bool {
3 if num < 1 {return false}
4 var number:Int = num
5 while (number % 2 == 0)
6 {
7 number /= 2
8 }
9 while (number % 3 == 0)
10 {
11 number /= 3
12 }
13 while (number % 5 == 0)
14 {
15 number /= 5
16 }
17 return number == 1
18 }
19 }
16ms
1 class Solution {
2 func maxDiv(_ num: inout Int, _ div: Int) {
3 while (num % div == 0) {
4 num = num/div
5 }
6 }
7
8 func isUgly(_ num: Int) -> Bool {
9 if(num == 0) {
10 return false
11 }
12 var no = num
13 maxDiv(&no, 2)
14 maxDiv(&no, 3)
15 maxDiv(&no, 5)
16
17 if(no == 1){
18 return true
19 }
20 else {
21 return false
22 }
23
24 }
25 }
20ms
1 class Solution {
2 func isUgly(_ num: Int) -> Bool {
3 guard num > 0 else {return false}
4 var n = num
5
6 let divs = [2, 3, 5]
7 for d in divs {
8 while n % d == 0 {
9 n /= d
10 }
11 }
12 return n == 1
13 }
14 }
转载于:https://www.cnblogs.com/strengthen/p/9751111.html