Remove first X rows and columns from a matrix

0 0 4 minutes read

Given an integer X and a square matrix mat[][], the task is to remove the first X rows and columns from the given matrix and print the updated matrix.

Examples:

Input: mat[][] = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{8, 9, 4, 2},
{4, 8, 9, 2} },
X = 2
Output:
4 2
9 2

Input: mat[][] = {
{1, 2, 3},
{4, 5, 6},
{7, 8, 9} },
X = 1
Output:
5 6
8 9

Approach: Print the elements of the matrix arr[i][j] for all i, j ? [X, N – 1] where N is the order of the given square matrix.

Below is the implementation of the above approach:

C++

// C++ implementation of the approach
#include <iostream>
using namespace std;
 
const int MAX = 50;
 
// Function to print the matrix after
// ignoring first x rows and columns
void remove_row_col(int arr[][MAX], int n, int x)
{
 
    // Ignore first x rows and columns
    for (int i = x; i < n; i++) {
        for (int j = x; j < n; j++) {
            cout << arr[i][j] << " ";
        }
        cout << endl;
    }
}
 
// Driver Code
int main()
{
 
    // Order of the square matrix
    int n = 3;
    int arr[][MAX] = { { 1, 2, 3 },
                       { 4, 5, 6 },
                       { 7, 8, 9 } };
 
    int x = 1;
    remove_row_col(arr, n, x);
}

Java

// Java implementation of the approach
 
import java.io.*;
 
class GFG 
{
 
static int MAX = 50;
 
// Function to print the matrix after
// ignoring first x rows and columns
static void remove_row_col(int arr[][], int n, int x)
{
 
    // Ignore first x rows and columns
    for (int i = x; i < n; i++) 
    {
        for (int j = x; j < n; j++)
        {
            System.out.print( arr[i][j] + " ");
        }
        System.out.println();
    }
}
 
// Driver Code
public static void main (String[] args) 
{
    // Order of the square matrix
    int n = 3;
    int arr[][] = { { 1, 2, 3 },
                    { 4, 5, 6 },
                    { 7, 8, 9 } };
 
    int x = 1;
    remove_row_col(arr, n, x);
}
}
 
// This code is contributed by 
// shk

Python3

# Python3 implementation of the approach 
 
# Function to print the matrix after 
# ignoring first x rows and columns 
def remove_row_col(arr, n, x): 
 
    # Ignore first x rows and columns 
    for i in range(x, n): 
        for j in range(x, n): 
            print(arr[i][j], end = " ") 
         
        print()
 
# Driver Code 
if __name__ == "__main__":
 
    # Order of the square matrix 
    n = 3
    MAX = 50
    arr = [[1, 2, 3], 
           [4, 5, 6], 
           [7, 8, 9]] 
 
    x = 1
    remove_row_col(arr, n, x) 
     
# This code is contributed by Rituraj Jain

C#

// C# implementation of the approach 
using System;
 
class GFG 
{ 
    // Function to print the matrix after 
    // ignoring first x rows and columns 
    static void remove_row_col(int [,]arr, int n, int x) 
    { 
     
        // Ignore first x rows and columns 
        for (int i = x; i < n; i++) 
        { 
            for (int j = x; j < n; j++) 
            { 
                Console.Write(arr[i, j] + " "); 
            } 
            Console.WriteLine(); 
        } 
    } 
     
    // Driver Code 
    public static void Main() 
    { 
        // Order of the square matrix 
        int n = 3; 
        int [,]arr = { { 1, 2, 3 }, 
                        { 4, 5, 6 }, 
                        { 7, 8, 9 } }; 
     
        int x = 1; 
        remove_row_col(arr, n, x); 
    } 
} 
 
// This code is contributed by Ryuga

PHP

<?php
// PHP implementation of the approach
 
$MAX = 50;
 
// Function to print the matrix after
// ignoring first x rows and columns
function remove_row_col($arr, $n, $x)
{
 
    // Ignore first x rows and columns
    for ($i = $x; $i < $n; $i++) 
    {
        for ($j = $x; $j < $n; $j++) 
        {
            echo $arr[$i][$j] . " ";
        }
        echo "\n";
    }
}
 
// Driver Code
 
// Order of the square matrix
$n = 3;
$arr = array(array( 1, 2, 3 ),
             array( 4, 5, 6 ),
             array( 7, 8, 9 ));
 
$x = 1;
remove_row_col($arr, $n, $x);
 
// This code is contributed by ihritik
?>

Javascript

<script>
 
// Javascript implementation of the approach
 
 
let MAX = 50;
 
// Function to print the matrix after
// ignoring first x rows and columns
function remove_row_col(arr,n,x)
{
 
    // Ignore first x rows and columns
    for (let i = x; i < n; i++)
    {
        for (let j = x; j < n; j++)
        {
            document.write( arr[i][j] + " ");
        }
        document.write("<br>");
    }
}
 
// Driver Code
 
    // Order of the square matrix
    let n = 3;
    let arr = [[ 1, 2, 3 ],
               [ 4, 5, 6 ],
               [ 7, 8, 9 ]];
 
    let x = 1;
    remove_row_col(arr, n, x);
 
 
// This code is contributed by sravan kumar
 
    </script>

Output

5 6 
8 9

Complexity Analysis:

Time Complexity: O(n^2), where n is an order of the given square matrix.
Auxiliary Space: O(1), as we are not using any extra space.

Feeling lost in the world of random DSA topics, wasting time without progress? It’s time for a change! Join our DSA course, where we’ll guide you on an exciting journey to master DSA efficiently and on schedule.
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 zambiatek!