Reverse Words in a String III

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Reverse each word individually in a sentence (preserving word order and spaces).

Example 1
Input: s="Let's take LeetCode contest" → Output: "s'teL ekat edoCteeL tsetnoc"
Example 2
Input: s="Mr Ding" → Output: "rM gniD"

Solution Approach

Split by spaces, reverse each word, join back.

  • Split by spaces
  • For each word: reverse it using StringBuilder
  • Join all reversed words with spaces
Java
public String reverseWords(String s) {
    String[] words = s.split(" ");
    StringBuilder sb = new StringBuilder();
    for (String w : words) {
        if (sb.length() > 0) sb.append(' ');
        sb.append(new StringBuilder(w).reverse());
    }
    return sb.toString();
}
  • Time Complexity: O(n)
  • Space Complexity: O(n)