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Php Program to Rotate the matrix right by K times

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  • Last Updated : 08 Jun, 2022

Given a matrix of size N*M, and a number K. We have to rotate the matrix K times to the right side. 
Examples: 
 

Input :  N = 3, M = 3, K = 2
         12 23 34
         45 56 67
         78 89 91 

Output : 23 34 12
         56 67 45
         89 91 78 


Input :  N = 2, M = 2, K = 2
         1 2
         3 4
         
Output : 1 2
         3 4

 

A simple yet effective approach is to consider each row of the matrix as an array and perform an array rotation. This can be done by copying the elements from K to end of array to starting of array using temporary array. And then the remaining elements from start to K-1 to end of the array.
Lets take an example: 
 

 

PHP




<?php
// PHP program to rotate
// a matrix right by k times
 
// size of matrix
$M = 3;
$N = 3;
 
// function to rotate
// matrix by k times
function rotateMatrix(&$matrix, $k)
{
    global $M, $N;
     
    // temporary array
    // of size M
    $temp = array();
     
    // within the size
    // of matrix
    $k = $k % $M;
     
    for ($i = 0; $i < $N; $i++)
    {
     
        // copy first M-k elements
        // to temporary array
        for ($t = 0;
             $t < $M - $k; $t++)
        $temp[$t] = $matrix[$i][$t];
     
        // copy the elements from
        // k to end to starting
        for ($j = $M - $k;
             $j < $M; $j++)
        $matrix[$i][$j - $M + $k] =
                    $matrix[$i][$j];
     
        // copy elements from
        // temporary array to end
        for ($j = $k; $j < $M; $j++)
        $matrix[$i][$j] = $temp[$j - $k];
    }
}
 
// function to display
// the matrix
function displayMatrix(&$matrix)
{
    global $M, $N;
    for ($i = 0; $i < $N; $i++)
    {
        for ($j = 0; $j < $M; $j++)
        echo ($matrix[$i][$j]." ");
        echo ("
");
    }
}
 
// Driver code
$matrix = array(array(12, 23, 34),
                array(45, 56, 67),
                array(78, 89, 91));
$k = 2;
 
// rotate matrix by k
rotateMatrix($matrix, $k);
 
// display rotated matrix
displayMatrix($matrix);
 
// This code is contributed by
// Manish Shaw(manishshaw1)
?>

Output: 

23 34 12 
56 67 45 
89 91 78

 

Time Complexity: O(N*M) 
Auxiliary Space: O(M)

Please refer complete article on Rotate the matrix right by K times for more details!


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