Reverse Each Word

/*
 * Problem : Reverse every word.
 * Input   : One line of text.
 * Output  : The line with reversed words.
 * Approach: Reverse inside each word.
 * Time    : O(n)
 * Space   : O(n)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static String solve(String s) {
        // Step 1: Split the line into words at single spaces.
        String[] words = s.split(" ");
        StringBuilder result = new StringBuilder();

        // Step 2: Handle one word at a time.
        for (int w = 0; w < words.length; w++) {
            // Step 3: Add the letters of the word from the last to the first.
            for (int i = words[w].length() - 1; i >= 0; i--) {
                result.append(words[w].charAt(i));
            }

            // Step 4: Put a space between words.
            if (w < words.length - 1) {
                result.append(" ");
            }
        }
        return result.toString();
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String s = scanner.hasNextLine() ? scanner.nextLine() : "";
        System.out.println(solve(s));
    }
}