Reverse Sentence Simple

ReverseSentenceNoPunctuation.java

//In-Place
public class ReverseSentenceInPlace
{
  public static void main(String[] args)
  {
    String str = "Hello, I would, like, to.....,... reverse!  This, sentence.,,";
    
    String reversed = reverseSentence(str);
   
    System.out.print(reversed);
  }
  
  public static String reverseSentence(String str){
    char[] arr = str.toCharArray();
    
    reverse(arr, 0, arr.length-1);
    
    for (int i = 0; i < arr.length; i++){
      int j = i;
      while (j < arr.length && arr[j] != ' '){
        j++;
      }
      reverse(arr, i, j-1);
      i = j;
    }
    
    return new String(arr);
    
  }
  
  public static void reverse(char[] arr, int start, int end){
    while (start < end){
      char temp = arr[start];
      arr[start] = arr[end];
      arr[end] = temp;
      start++;
      end--;
    }
  }
  
}
/*output:
sentence.,, This,  reverse! to.....,... like, would, I Hello,
*/

//using split method
public class Solution {
    public String reverseWords(String s) {
        s = s.trim();
        String[] words = s.split(" +");
        StringBuffer strBuff = new StringBuffer();

        if (words.length != 0) {
            for (int i = words.length - 1; i > 0; i--) {
                strBuff.append(words[i] + " ");
            }
            strBuff.append(words[0]);
        }

        return strBuff.toString();
    }
}