<?php
$input = file('input', FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
$input = array_map('str_split', $input);

$chunkPairs = [
    ')' => '(',
    ']' => '[',
    '>' => '<',
    '}' => '{',
];
$values = [
    '(' => 1,
    '[' => 2,
    '{' => 3,
    '<' => 4,
];
$scores = [];
foreach ($input as $line) {
    $tmpBuffer = [];
    foreach ($line as $charPos => $char) {
        if (in_array($char, array_values($chunkPairs))) {
            $tmpBuffer[] = $char;
        }
        if (in_array($char, array_keys($chunkPairs))) {
            $lastBufferItem = array_pop($tmpBuffer);
            if ($chunkPairs[$char] !== $lastBufferItem) {
                continue 2;
            }
        }
    }
    $score = 0;
    foreach (array_reverse($tmpBuffer) as $bufferChar) {
        $score *= 5;
        $score += $values[$bufferChar];
    }
    $scores[] = $score;
}
sort($scores);
print_r($scores);
print_r($scores[floor(count($scores) / 2)]); //1118645287