Question

In Java

Write a routine which will take a string of characters consisting of just the letters A B and C and rearrange the string so that at the end of the code there will first be all the "A" 's then all the "B" 's and then all the "C" 's. Example string "ACBBACABC" should end up "AAABBBCCC"

Answer 1

package com.company;
import java.util.*;
public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter a string that only contains A, B or C: ");
        String str = sc.nextLine();

        String[] letters = str.split("");

        for (int i = 0; i < letters.length; i++) {
            if (letters[i].equals("A") || letters[i].equals("B") || letters[i].equals("C")) {
                continue;
            }
            else {
                System.exit(-1);
            }
        }

        /* calling function to sort */
        convert(letters);

        /* displaying result */
        for (int i = 0; i < letters.length; i++) {
            System.out.print(letters[i]);
        }
    }

    /* method for sorting string in ascending with all A's at first then all B's and then C's */
    public static String[] convert(String[] str) {
        String temp;
        for (int i = 0; i < str.length; i++) {
            for (int j = 0; j < str.length; j++) {

                /* comparing characters and swapping their positions if compareTo is not 0 */
                if (str[i].compareTo(str[j]) < 0) {
                    temp = str[j];
                    str[j] = str[i];
                    str[i] = temp;
                }
            }
        }

        /* returning sorted list */
        return str;
    }
}

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Thank You