leetcode 434. 字符串中的单词数（Java版）

r囧r小猫 2023-01-17 07:47 163阅读 0赞

## 题目 ##

[https://leetcode-cn.com/problems/number-of-segments-in-a-string/][https_leetcode-cn.com_problems_number-of-segments-in-a-string]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70]

#### 几个小坑 ####

列一下几个有代表性的易错输入吧（可能会有多个连续空格）：

"      "
    "    Hello, my name is             John"
    "Hello, my name is John"

## 题解 ##

一开始的思路是识别空格的个数，后来发现测试用例会有多个连续的空格存在。于是想到了可以通过“空格+非空格”的形式，去统计单词的个数。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70 1]

## 代码 ##

public class Solution { 
        public int countSegments(String s) { 
            if (s.length() == 0) return 0;
            char[] chars = s.toCharArray();
            int cnt = 0;
            if (chars[0] != ' ') cnt++; // 第一个单词需要独立判断
            for (int i = 0; i < chars.length - 1; i++) { 
                if (chars[i] == ' ' && chars[i + 1] != ' ') cnt++;
            }
            return cnt;
        }
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70 2]

[https_leetcode-cn.com_problems_number-of-segments-in-a-string]: https://leetcode-cn.com/problems/number-of-segments-in-a-string/
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70]: /images/20221021/21c639a537ae48b4953c659a2969698a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70 1]: /images/20221021/c890c1a0f50d4f52bb739cd7992a8e04.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzQyNDgzMzQx_size_16_color_FFFFFF_t_70 2]: /images/20221021/6e98489b8147484abde9850b45aa3c85.png