Open In App

PHP Program to Sort the matrix row-wise and column-wise

Last Updated : 22 Jul, 2024
Comments
Improve
Suggest changes
Like Article
Like
Report

Given a n x n matrix. The problem is to sort the matrix row-wise and column-wise.

Examples: 

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

Input : mat[][] = { {12, 7, 1, 8},
{20, 9, 11, 2},
{15, 4, 5, 13},
{3, 18, 10, 6} }
Output : 1 5 8 12
2 6 10 15
3 7 11 18
4 9 13 20

Approach:

Follow the below steps:

  1. Sort each row of the matrix.
  2. Get transpose of the matrix.
  3. Again sort each row of the matrix.
  4. Again get transpose of the matrix.

Algorithm for getting transpose of the matrix: 

for (int i = 0; i < n; i++) {
for (int j = i + 1; i < n; i++) {
int temp = mat[i][j];
mat[i][j] = mat[j][i];
mat[j][i] = temp;
}
}

Below is the implementation of above approach:

PHP
<?php
// PHP implementation to sort 
// the matrix row-wise and 
// column-wise
$MAX_SIZE = 10;

// function to sort each
// row of the matrix
function sortByRow(&$mat, $n)
{
    for ($i = 0; $i < $n; $i++)

        // sorting row number 'i'
        sort($mat[$i]);
}

// function to find
// transpose of the matrix
function transpose(&$mat, $n)
{
    for ($i = 0; $i < $n; $i++)
    {
        for ($j = $i + 1; 
             $j < $n; $j++) 
        {
            // swapping element at index (i, j) 
            // by element at index (j, i)
            $t = $mat[$i][$j];
            $mat[$i][$j] = $mat[$j][$i];
            $mat[$j][$i] = $t;
        }
    }
}

// function to sort 
// the matrix row-wise
// and column-wise
function sortMatRowAndColWise(&$mat, $n)
{
    // sort rows of mat[][]
    sortByRow($mat, $n);

    // get transpose of mat[][]
    transpose($mat, $n);

    // again sort rows of mat[][]
    sortByRow($mat, $n);

    // again get transpose of mat[][]
    transpose($mat, $n);
}

// function to print the matrix
function printMat(&$mat, $n)
{
    for ($i = 0; $i < $n; $i++) 
    {
        for ($j = 0; $j < $n; $j++)
            echo $mat[$i][$j] . " ";
        echo "
";
    }
}

// Driver Code
$mat = array(array( 4, 1, 3 ),
             array( 9, 6, 8 ),
             array( 5, 2, 7 ));
$n = 3;

echo "Original Matrix:
";
printMat($mat, $n);

sortMatRowAndColWise($mat, $n);

echo "
Matrix After Sorting:
";
printMat($mat, $n);

// This code is contributed 
// by ChitraNayal
?>

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

Matrix After Sorting:
1 3 4 
2 5 7 
6 8 9 

Complexity Analysis:

  • Time Complexity: O(n2log2n). 
  • Auxiliary Space: O(1).

Please refer complete article on Sort the matrix row-wise and column-wise for more details!


Next Article
Practice Tags :

Similar Reads