<?php
function is_valid($string) {
do {
$string = str_replace(['()', '{}', '[]'], '', $string, $count);
} while ($count);
return (int)!$string;
}
$expressions = array(")(){}", "[]({})", "([])", "{()[]}", "([)]", "{()[]}{()[]}{()[]}{()[]}{()[]}");
foreach ($expressions as $expression) {
echo "$expression is " , is_valid($expression) , "\n";
}
preferences:
25.25 ms | 404 KiB | 5 Q