braces_puzzle.php

<?php

function check_braces($expressions) {

    for($x = 0; $x < count($expressions); $x++)
    {
        $open = array("{", "[", "(");
        $close = array("}", "]", ")");
        $key = array("{" => "}", "[" => "]", "(" => ")");
        $string = $expressions[$x];
        echo $string."<br>";
        
        //First item should open a brace, else fail
        if((in_array($string[0], $close)) && (strlen($string) % 2))
        {
            echo 0;
            echo '<br>';  
        }
        else
        {
            $bank_o = array();
            $bank_c = array();
            $element = array();

            for($y = 0; $y < strlen($string); $y++)
            {
                $element = $string[$y];

                if(in_array($element, $open))
                {
                    array_push($bank_o, $element);
                }
                else
                {
                    array_push($bank_c, $element);
                }

                $arraycounter = array_merge($bank_o, $bank_c);

                $y++;

                if(!empty($bank_c) && !empty($bank_o))
                {
                    $num = count($bank_o);
                    if($bank_c[0] == $key[$bank_o[$num - 1]])
                    {
                        array_shift($bank_c);
                        array_pop($bank_o);
                    }
                }
                elseif (empty($bank_c) && empty($bank_o)) {
                    echo 1 . "<br>";
                }
                else
                {

                }

            }
        }
    }
}

//$expressions = array(")(){}","[]({})","([])","{()[]}","([)]");

$expressions = array("([])","([)]");

check_braces($expressions);

?>