[Swift]LeetCode434. 字符串中的单词数 | Number of Segments in a String

★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
➤微信公众号：山青咏芝（shanqingyongzhi）
➤博客园地址：山青咏芝（https://www.cnblogs.com/strengthen/）
➤GitHub地址：https://github.com/strengthen/LeetCode
➤原文地址：https://www.cnblogs.com/strengthen/p/9783619.html 
➤如果链接不是山青咏芝的博客园地址，则可能是爬取作者的文章。
➤原文已修改更新！强烈建议点击原文地址阅读！支持作者！支持原创！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★

Count the number of segments in a string, where a segment is defined to be a contiguous sequence of non-space characters.

Please note that the string does not contain any non-printable characters.

Example:

Input: "Hello, my name is John"
Output: 5

---

统计字符串中的单词个数，这里的单词指的是连续的不是空格的字符。

请注意，你可以假定字符串里不包括任何不可打印的字符。

示例:

输入: "Hello, my name is John"
输出: 5

---

8ms

class Solution {
    func countSegments(_ s: String) -> Int {
        if s == nil || s.count == 0 {return 0}
        var word:Int = 0
        var count:Int = 0
        //按索引遍历
        for i in s.indices
        {
            if s[i] == " "
            {
                if word > 0
                {
                    count += 1
                    word = 0
                }
            }
            else
            {
                word += 1
            }            
        }
        if word > 0
        {
            count += 1
        }
        return count
    }
}

---

8ms

class Solution {
    func countSegments(_ s: String) -> Int {
        var count = 0
        var segmentInProgress = false
        for char in s {
            if char != " " && !segmentInProgress {
                count += 1
                segmentInProgress = true
            } else if char == " " {
                segmentInProgress = false
            }
        }
        
        return count
    }
}

---

12ms

class Solution {
    func countSegments(_ s: String) -> Int {
        return s.split(separator: " ").count
    }
}

---

16ms

class Solution {
    func countSegments(_ s: String) -> Int {
        return s.characters.split(separator: " ").count
    }
}