Question

I need it in Java please. please help asap. TIA.

Give a linear-time algorithm for reversing a string.

Answer 1

import java.util.Scanner;

public class ReverseString {

    /**
     * Liner time algorithm for reversing a string
     * @param s
     * @return
     */
    static String reverseString(String s) {
        String result = "";
        for(int i = 0; i < s.length(); ++i) {   // iterate through all indices
            result += s.charAt(s.length() - i - 1); // add a character from end of the string
        }
        return result;  // return string
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String line = in.nextLine();
        System.out.println("The reverse of \"" + line + "\" is \"" + reverseString(line) + "\".");
    }

}