Java Exercises: Find the row, column position of a specified number in a given 2-dimensional array

Java Search: Exercise-7 with Solution

Given is a 2-dimensional integer array [0..m-1, 0..n-1], each row and column of which is in ascending order (see example).

Example:

Write a Java program to find the row, column position of a specified number (row, column position) in a given 2-dimensional array.

Sample Solution:

Java Code:

import java.util.*;
public class abc {

  public static void main(String[] args) {
   int nums[][] = {{12, 20, 30, 40}, 
                  {15, 25, 35, 45}, 
                  {24, 29, 39, 51}, 
                  {35, 30, 39, 50}, 
                  {50, 60, 75, 72}}; 
			   
	 int rows = 5;    
	 int search_element = 39;		   
     int ans[] = Saddleback(nums, rows - 1, 0, search_element);
        System.out.println("Position of "+search_element+" in the matrix is ("+ans[0] + "," + ans[1]+")");			   
    } 

    /**
     * @param nums, the matrix.  
     * @param row the current row.
     * @param col the current column.
     * @param search_element  the element that we want to search for.
     * @return value: If found the index(row and column) of the element.
     *  else return (-1 -1).
     */
    private static int[] Saddleback(int nums[][], int row, int col, int search_element) {

        //numsay to store the row and column of the searched element
        int element_pos[] = {-1, -1};
        if (row < 0 || col >= nums[row].length) {
            return element_pos;
        }
        if (nums[row][col] == search_element) {
            element_pos[0] = row;
            element_pos[1] = col;
            return element_pos;
        }
        //move up if the current element is greater than the given element  
        else if (nums[row][col] > search_element) {
            return Saddleback(nums, row - 1, col, search_element);
        }
        //otherwise move right
        return Saddleback(nums, row, col + 1, search_element);
    }

    /**
     * Main method
     *
     * @param args Command line arguments
     */
  
}

Sample Output:

Position of 39 in the matrix is (3,2)

Flowchart:

Java Code Editor:

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