Exploring Spiral Matrix Traversal in PHP

Introduction: In the realm of programming, there are various ways to traverse and manipulate arrays. One intriguing method is spiral matrix traversal, a technique that moves through a 2D array in a spiral fashion. In this blog post, we'll delve into a PHP program that demonstrates spiral matrix traversal and discuss the logic behind it.

Understanding the Spiral Matrix Traversal Program:

<?php
$main_array = [
    [1, 2, 3, 4, 5],
    [16, 17, 18, 19, 6],
    [15, 24, 25, 20, 7],
    [14, 23, 22, 21, 8],
    [13, 12, 11, 10, 9]
];

 

$left = 0;
$right = sizeOf($main_array[0]) - 1;
$top = 0;
$bottom = sizeOf($main_array) - 1;

$final_array = array();
while ($top <= $bottom && $left <= $right) {
    for ($i=$left; $i <= $right; $i++) {
        array_push($final_array, $main_array[$top][$i]);
    }
    $top++;

    for ($i = $top; $i <= $bottom; $i++) {
        array_push($final_array, $main_array[$i][$right]);
    }
    $right--;

    if ($top <= $bottom) {
        for ($i = $right; $i >= $left; $i--) {
            array_push($final_array, $main_array[$bottom][$i]);
        }
        $bottom--;
    }

    if ($left <= $right) {
        for ($i = $bottom; $i >= $top; $i--) {
            array_push($final_array, $main_array[$i][$left]);
        }
        $left++;
    }
}

echo json_encode($final_array);
?>

Breaking Down the Logic:

1. Initialization:

   • The program starts with the definition of a 2D array named $main_array representing a matrix.

2. Variable Initialization:

   • $left, $right, $top, and $bottom variables are initialized to keep track of the boundaries.

3. Traversal:

   • The program uses a while loop to traverse the matrix in a spiral manner.
   • It employs four for loops, each handling one side of the matrix, pushing elements into the $final_array.

4. Adjusting Boundaries:

   • After each traversal of a side, the corresponding boundary is adjusted to ensure the next traversal covers the correct elements.

5. Printing the Result:

   • The final result is echoed as a JSON-encoded array.

Conclusion: Spiral matrix traversal is a fascinating algorithmic concept, and the provided PHP program showcases an implementation of this technique. Understanding and implementing such algorithms not only enhances problem-solving skills but also provides valuable insights into array manipulation.

Feel free to experiment with different matrices or integrate this logic into larger projects to explore its practical applications. Happy coding!