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Interchange elements of first and last columns in matrix

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Given a square matrix, the task is to interchange the elements of the first and last columns and show the resulting matrix

Examples: 

Input:   8 9 7 6
             4 7 6 5
             3 2 1 8
             9 9 7 7

Output:  6 9 7 8
               5 7 6 4
               8 2 1 3
               7 9 7 9

Input:  9 7 5 1
            2 3 4 1
            5 6 6 5
            1 2 3 1

Output:   1 7 5 9
                1 3 4 2
                5 6 6 5
                1 2 3 1

Recommended Practice

To solve the problem follow the below idea:

Simply swap the elements of the first and last column of the matrix in order to get the desired matrix as output

Below is the implementation of the above approach: 

C++




// C++ code to swap the element of first
// and last column and display the result
#include <iostream>
using namespace std;
 
#define n 4
 
void interchangeFirstLast(int m[][n])
{
    // swapping of element between first
    // and last columns
    for (int i = 0; i < n; i++) {
        int t = m[i][0];
        m[i][0] = m[i][n - 1];
        m[i][n - 1] = t;
    }
}
 
// Driver code
int main()
{
    // input in the array
    int m[n][n] = { { 8, 9, 7, 6 },
                    { 4, 7, 6, 5 },
                    { 3, 2, 1, 8 },
                    { 9, 9, 7, 7 } };
 
    // Function call
    interchangeFirstLast(m);
 
    // printing the interchanged matrix
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++)
            cout << m[i][j] << " ";
        cout << endl;
    }
}


Java




// Java code to swap the element of first
// and last column and display the result
 
import java.io.*;
 
class GFG {
 
    static int n = 4;
 
    static void interchangeFirstLast(int m[][])
    {
        int cols = n;
 
        // swapping of element between first
        // and last columns
        for (int i = 0; i < n; i++) {
            int t = m[i][0];
            m[i][0] = m[i][n - 1];
            m[i][n - 1] = t;
        }
    }
 
    // Driver code
    public static void main(String[] args)
    {
        // input in the array
        int m[][] = { { 8, 9, 7, 6 },
                      { 4, 7, 6, 5 },
                      { 3, 2, 1, 8 },
                      { 9, 9, 7, 7 } };
 
        // Function call
        interchangeFirstLast(m);
 
        // printing the interchanged matrix
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++)
                System.out.print(m[i][j] + " ");
            System.out.println();
        }
    }
}
// This code is contributed by inder_verma


Python 3




# Python3 code to swap the element of
# first and last column and display
# the result
 
 
def interchangeFirstLast(mat, n, m):
    rows = n
 
    # swapping of element between
    # first and last columns
    for i in range(n):
        t = mat[i][0]
        mat[i][0] = mat[i][n-1]
        mat[i][n-1] = t
 
 
# Driver code
if __name__ == "__main__":
    mat = [[8, 9, 7, 6],
           [4, 7, 6, 5],
           [3, 2, 1, 8],
           [9, 9, 7, 7]]
 
    n = 4
    m = 4
 
    # Function call
    interchangeFirstLast(mat, n, m)
 
    # printing the interchanged matrix
    for i in range(n):
        for j in range(m):
            print(mat[i][j], end=" ")
        print("\n")


C#




// C# code to swap the element of first
// and last column and display the result
using System;
 
class GFG {
 
    static int n = 4;
 
    static void interchangeFirstLast(int[, ] m)
    {
 
        // swapping of element between first
        // and last columns
        for (int i = 0; i < n; i++) {
            int t = m[i, 0];
            m[i, 0] = m[i, n - 1];
            m[i, n - 1] = t;
        }
    }
 
    // Driver Code
    public static void Main()
    {
        // input in the array
        int[, ] m = { { 8, 9, 7, 6 },
                      { 4, 7, 6, 5 },
                      { 3, 2, 1, 8 },
                      { 9, 9, 7, 7 } };
 
        // Function call
        interchangeFirstLast(m);
 
        // printing the interchanged matrix
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++)
                Console.Write(m[i, j] + " ");
            Console.WriteLine();
        }
    }
}
 
// This code is contributed
// by Akanksha Rai


PHP




<?php
// PHP code to swap the element of first
// and last column and display the result
 
function interchangeFirstLast($m, $n)
{
    $cols = $n;
 
    // swapping of element between first
    // and last columns
    for ($i = 0; $i < $n; $i++)
    {
        $t = $m[$i][0];
        $m[$i][0] = $m[$i][$n - 1];
        $m[$i][$n - 1] = $t;
    }
    return $m ;
}
     
// Driver Code
 
// input in the array
$m = array( array( 8, 9, 7, 6 ),
            array (4, 7, 6, 5 ),
            array (3, 2, 1, 8 ),
            array (9, 9, 7, 7 ));
 
$n = 4 ;
 
// Function call
$m = interchangeFirstLast($m,$n);
 
// printing the interchanged matrix
for ($i = 0; $i < $n; $i++)
{
    for ($j = 0; $j < $n; $j++)
        echo $m[$i][$j], " ";
         
    echo "\n" ;
}
 
// This code is contributed by Ryuga
?>


Javascript




<script>
 
// Javascript code to swap the element of first
// and last column and display the result
n = 4
 
function interchangeFirstLast(m)
{
    // swapping of element between first
    // and last columns
    for (var i = 0; i < n; i++)
    {
        var t = m[i][0];
        m[i][0] = m[i][n - 1];
        m[i][n - 1] = t;
    }
}
 
// Driver function
// input in the array
m = [ [ 8, 9, 7, 6 ],
                [ 4, 7, 6, 5 ],
                [ 3, 2, 1, 8 ],
                [ 9, 9, 7, 7 ] ];
interchangeFirstLast(m);
 
// printing the interchanged matrix
for (var i = 0; i < n; i++)
{
    for (var j = 0; j < n; j++)
        document.write( m[i][j] + " ");
    document.write("<br>");
}
 
// This code is contributed by noob2000.
</script>


Output

6 9 7 8 
5 7 6 4 
8 2 1 3 
7 9 7 9 

Time Complexity: O(N2)
Auxiliary Space: O(1)



Last Updated : 20 Mar, 2023
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