How can PHP arrays and functions like array_map be utilized to check the validity of a Sudoku game?

To check the validity of a Sudoku game, we can utilize PHP arrays and functions like array_map to compare rows, columns, and subgrids for duplicate values. We can create functions to check each of these components separately and then combine them to validate the entire Sudoku game.

```php
function isValidSudoku($board) {
    // Check rows
    foreach ($board as $row) {
        if (!isValid($row)) {
            return false;
        }
    }
    
    // Check columns
    for ($i = 0; $i &lt; 9; $i++) {
        $col = array_column($board, $i);
        if (!isValid($col)) {
            return false;
        }
    }
    
    // Check subgrids
    for ($i = 0; $i &lt; 9; $i += 3) {
        for ($j = 0; $j &lt; 9; $j += 3) {
            $subgrid = [];
            for ($k = $i; $k &lt; $i + 3; $k++) {
                for ($l = $j; $l &lt; $j + 3; $l++) {
                    $subgrid[] = $board[$k][$l];
                }
            }
            if (!isValid($subgrid)) {
                return false;
            }
        }
    }
    
    return true;
}

function isValid($arr) {
    $counts = array_count_values($arr);
    foreach ($counts as $value) {
        if ($value &gt; 1 &amp;&amp; $value !== &#039;&#039;) {
            return false;
        }
    }
    return true;
}

// Example Sudoku board
$board = [
    [5, 3, &#039;&#039;, &#039;&#039;, 7, &#039;&#039;, &#039;&#039;, &#039;&#039;, &#039;&#039;],
    [6, &#039;&#039;, &#039;&#039;, 1, 9, 5, &#039;&#039;, &#039;&#039;, &#039;&#039;],
    [&#039;&#039;, 9, 8, &#039;&#039;, &#039;&#039;, &#039;&#039;, &#039;&#039;, 6, &#039;&#039;],
    [8, &#039;&#039;, &#039;&#039;, &#039;&#039;, 6, &#039;&#039;, &#039;&#039;, &#039;&#039;, 3],
    [4, &#039;&#039;, &#039;&#039;, 8, &#039;&#039;, 3, &#039;&#039;, &#039;&#039;, 1],
    [7, &#039;&#039;, &#039;&#039;, &#039;&#039;, 2, &#039;&#039;, &#039;&#039;, &#039;&#039;, 6],
    [&#039;&#039;, 6, &#039;&#039;, &#039;&#039;, &#039;&#039;, &#039;&#039;, 2, 8, &#039;&#039;],
    [&#039;&#039;, &#039;&#039;, &#039;&#039;, 4, 1, 9, &#039;&#039;, &#039;&#039;, 5],
    [&#039;&#039;, &#039;&#039;, &#039;&#039;, &#039;&#039;, 8, &#039;&#039;, &#039;&#039;, 7,

Keywords

PHP arrays array_map Sudoku game validity

How can PHP arrays and functions like array_map be utilized to check the validity of a Sudoku game?

Keywords

Related Questions