LeetCode_ String inversion_ Simple_ 557. Reverse word III in string

1. subject

Given a string s , You need to reverse the character order of each word in the string , Keep the initial order of spaces and words .

Example 1：

Input ：s = “Let’s take LeetCode contest”
Output ：“s’teL ekat edoCteeL tsetnoc”
Example 2：

Input ： s = “God Ding”
Output ：“doG gniD”

Tips ：
1 <= s.length <= 5 * 10⁴
s Include printable ASCII character .
s Does not contain any beginning or ending spaces .
s There is at least one word in it .
s All words in the are separated by a space .

source ： Power button （LeetCode）
link ：https://leetcode.cn/problems/reverse-words-in-a-string-iii

2. Ideas

（1） String inversion

3. Code implementation （Java）

// Ideas 1———— String inversion 
class Solution {
    
    public String reverseWords(String s) {
    
        StringBuffer res = new StringBuffer();
        int length = s.length();
        int i = 0;
        while (i < length) {
    
            // Record the starting subscript of the current word 
            int index = i;
            // Find the ending subscript of the current word 
            while (i < length && s.charAt(i) != ' ') {
    
                i++;
            }
            // Reverse the current word 
            for (int j = index; j < i; j++) {
    
                res.append(s.charAt(i - j - 1 + index));
            }
            // Keep spaces between words 
            while (i < length && s.charAt(i) == ' ') {
    
                i++;
                res.append(' ');
            }
        }
        return res.toString();
    }
}