LeetCode - Reverse Words in a String

Given an input string, reverse the string word by word.

Example 1:

Input: “the sky is blue” Output: “blue is sky the”

Example 2:

Input: ” hello world! ” Output: “world! hello” Explanation: Your reversed string should not contain leading or trailing spaces.

Example 2:

Input: “a good example” Output: “example good a” Explanation: You need to reduce multiple spaces between two words to a single space in the reversed string.

Solution

We can use Space as a tokenizer to split the string, Iterate array from end element and accumulate none empty string to the result string.

Code


public class ReverseWords {

	public static void main(String[] args) {
		
		String s="the sky is blue";
		System.out.println(new ReverseWords().reverseWords(s));

	}

    public String reverseWords(String s) {
        
        s=s.trim();  // Triming will take care tailing space.
        String sArr [] =s.split(" "); //Split with Space.
        String result="";


        for(int i=sArr.length-1;i>=0;i--){
            
            if(!sArr[i].trim().equals("")){
                result+=sArr[i]+" ";
            }
        }
        
        return result.trim();
    }
}