Question

How to check whether a matrix is a magic square or not in Java

Answer 1

public class MagicSquareChecker {

    // Function to check if the matrix is a magic square
    public static boolean isMagicSquare(int[][] matrix) {
        int size = matrix.length; // rows
        int sumDiagonal1 = 0, sumDiagonal2 = 0;

        // Calculate the sum of the primary diagonal
        for (int i = 0; i < size; i++) {
            sumDiagonal1 += matrix[i][i];
        }

        // Calculate the sum of the secondary diagonal
        for (int i = 0; i < size; i++) {
            sumDiagonal2 += matrix[i][size - i - 1];
        }

        // If the two diagonals don't have the same sum, it's not a magic square
        if (sumDiagonal1 != sumDiagonal2) {
            return false;
        }

        // Check sums of each row and column
        for (int i = 0; i < size; i++) {
            int sumRow = 0, sumCol = 0;

            for (int j = 0; j < size; j++) {
                sumRow += matrix[i][j];  // Sum of the current row
                sumCol += matrix[j][i];  // Sum of the current column
            }

            // If any row or column sum is not equal to the diagonal sum, it's not a magic square
            if (sumRow != sumDiagonal1 || sumCol != sumDiagonal1) {
                return false;
            }
        }

        // If all checks pass, it's a magic square
        return true;
    }

    public static void main(String[] args) {
        int[][] matrix = {
            {8, 3, 4},
            {1, 5, 9},
            {6, 7, 2}
        };

        // Check if the matrix is a magic square
        if (isMagicSquare(matrix)) {
            System.out.println("The given matrix is a magic square.");
        } else {
            System.out.println("The given matrix is NOT a magic square.");
        }
    }
}


/*
run:

The given matrix is a magic square.

*/

 

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