Question

How to calculate the median of a matrix in Java

Answer 1

import java.util.Arrays;

public class MedianMatrix {

    // Step 1: Flatten the matrix into a single array
    public static double findMedianUnsortedMatrix(int[][] matrix) {
        int rows = matrix.length;
        int cols = matrix[0].length;
        int total = rows * cols;

        int[] elements = new int[total];
        int k = 0;

        for (int[] row : matrix) {
            for (int val : row) {
                elements[k++] = val;
            }
        }

        // Step 2: Sort the elements
        Arrays.sort(elements);

        // Step 3: Calculate median
        if (total % 2 == 1) {
            // Odd number of elements: return middle element
            return elements[total / 2];
        } else {
            // Even number of elements: return average of two middle elements
            return (elements[total / 2 - 1] + elements[total / 2]) / 2.0;
        }
    }

    public static void main(String[] args) {
        int[][] matrix = {
            {5, 8, 9, 10},
            {1, 4, 6, 13},
            {7, 3, 0, 18},
            {6, 8, 9, 20}
        };

        double median = findMedianUnsortedMatrix(matrix);
        System.out.printf("Median of the matrix is: %.1f%n", median);
    }
}


/*
run:

Median of the matrix is: 7.5

*/

 

70+ SQL courses for beginners and professionals