<?php
function is_valid($string) {
return preg_match('~(\((?1)*+\)|\[(?1)*+]|{(?1)*+})*\z~A', $string);
}
$expressions = array(")(){}", "[]({})", "([])", "{()[]}", "([)]", "{()[]}{()[]}{()[]}{()[]}{()[]}");
foreach ($expressions as $expression) {
echo "$expression is " , is_valid($expression) , "\n";
}
- Output for 5.6.38, 7.1.0 - 7.1.23, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
- )(){} is 0
[]({}) is 1
([]) is 1
{()[]} is 1
([)] is 0
{()[]}{()[]}{()[]}{()[]}{()[]} is 1
preferences:
114.68 ms | 408 KiB | 5 Q