Question

Chapter 8 Exercise 36, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

8.36 (Latin square) A Latin square is an n-by-n array filled with n different Latin letters, each occurring exactly once in each row and once in each column. Write a program that prompts the user to enter the number n and the array of characters, as shown in the sample output, and checks if the input array is a Latin square.
The characters are the first n characters starting from A .
Enter number n: 4
Enter 4 rows of letters separated by spaces:
A B C D
B A D C
C D B A
D C A B
The input array is a Latin square
Enter number n: 3
Enter 3 rows of letters separated by spaces:
A F D
Wrong input: the letters must be from A to C

Outline for the source code

import java.util.Scanner;

public class LatinSquares {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.print("Enter n number: ");
        int n = input.nextInt();
        char[][] m = new char[n][n];
        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[i].length; j++) {
                m[i][j] = input.next().charAt(0);
            }
        }

        System.out.println(checkLatinSquare(m));

    }

    public static boolean checkLatinSquare(char[][] m) {

        // first check if grid has valid letters
        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[i].length; j++) {
            //More statements
            //Do something
            }
         }
     }
     // check if every row has unique letters
     for (int i = 0; i < m.length; i++) {
            if (!isRowValid(m, i)) return false;
        }

        // check if every column has unique letters
        for (int j = 0; j < m[0].length; j++) {
            if (!isColumnValid(m,j)) return false;
        }

        return true;
    }
    public static boolean isColumnValid(char[][] m, int column) {
         //Statements 
    }
    public static boolean isRowValid(char[][] m, int row) {
         //Statements
    }

    public static void displayMatrix(char[][] m) {
        //Statements
    }

    public static boolean isValidLetter(char ch, int n) {
        // ch starts off from A, so subtract one from n
        n--;
        return (ch >= 'A' && ch <= 'A' + n);
    }


}

Answer 1

import java.util.Scanner;

public class LatinSquares {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        System.out.print("Enter n number: ");
        int n = input.nextInt();
        char[][] m = new char[n][n];
        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[i].length; j++) {
              
               //More statements
                //Do something
                m[i][j] = input.next().charAt(0);
            }
        }

        if(checkLatinSquare(m))
           System.out.println("The input array is latin Square");
        else
           System.out.println("The input array is not latin Square");

    }

    public static boolean checkLatinSquare(char[][] m) {

        // first check if grid has valid letters
        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[i].length; j++) {

                if (!isValidLetter(m[i][j], m.length)) {
                    System.out.println("Wrong input:");
                    System.out.println("the letters must be from " + 'A' + "-" +(char)('A' + m.length - 1));
                    return false;
                }
            }
        }
        // check if every row has unique letters
        for (int i = 0; i < m.length; i++) {
            if (!isRowValid(m, i)) return false;
        }

        // check if every column has unique letters
        for (int j = 0; j < m[0].length; j++) {
            if (!isColumnValid(m,j)) return false;
        }

        return true;
    }
    public static boolean isColumnValid(char[][] m, int column) {
      
       //statements

        int[] used = new int[m.length];

        for (int i = 0; i < m.length; i++) {

            int index = m[i][column] - 'A';

            if (used[index]==1) {
                return false;
            } else {
               used[index] = 1;
            }
        }

        return true;
    }
    public static boolean isRowValid(char[][] m, int row) {
       //statements

        int[] used = new int[m.length];

        for (int j = 0; j < m[row].length; j++) {

            int index = m[row][j] - 'A';

            if (used[index]==1) {
                return false;
            } else {
               used[index] = 1;
            }
        }

        return true;
    }

    public static void displayMatrix(char[][] m) {
       //statements

        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[i].length; j++) {
                System.out.print(m[i][j] + " ");
            }
            System.out.println("");
        }
    }

    public static boolean isValidLetter(char ch, int n) {
        // ch starts off from A, so subtract one from n
        n--;
        return (ch >= 'A' && ch <= 'A' + n);
    }

}
=====================================================================

See The Output

1 import java.util.scanner 3 public class LatinSquares 5 public static void main(String[] args) くterminated> LatinSquares [Java Application] Enter n number: 4 A B CD BADC CD BA DCAB The input array is latin Square Scanner inputnew Scanner(System.in); System. out.print("Enter n number:" int n = input.nextInt(); char C]] mnew char[n] n]; for (int i 0; i < m.length; i+) f 10 for (int j = 0; j < m[i]. length; j++) { 12 13 14 /More statements //Do something m[i]05]-input.next).charAt(0); 16 17 18 19 20 21 if(checkLatinSquare(m)) System.out.println("The input array is latin Square" else 23 24 25 26 27 public static boolean checkLatinSquare(charm) 28 29 30 31 32 System.out.printlnC"The input array is not latin Square; //first check if grid has valid letters for (int i-; < m.length; i+) for (int j-0; j < mCi].Length; j++) f if C!isValidLetter(mCi]lj], m.length)) System.out.println( "Wrong input:" System.out.println("the letters must be from "'A' return false; "-" har)C'Am.length - 1 35 36 37 38 39 40 41 // check if every row has unique letters for (int i 0; i < m.length: i+)

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