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collection_mystery4

Language/Type: PHP collections Stack Queue
Author: Melissa Hovik (on 2018/01/05)

Write the result returned by the following function when passed each of the following stacks. Your answer should be in the same notation as the input collection (a comma-separated array surrounded by [] brackets). Note that a stack prints in [bottom ... top] order. 

function collection_mystery4($stack) {
    $queue = [];
    $set = [];
    while (count($stack) > 0) {
        $n = array_pop($stack);
        if ($n % 2 == 0) {
            array_push($queue, $n);
        } else {
            if (!in_array($n, $set)) {
                array_push($set, $n);
            }
        }
    }
    sort($set);
    foreach ($set as $n) {
        array_push($stack, $n);
    }
    while (count($queue) > 0) {
        array_push($stack, array_shift($queue));
    }
    return $stack;
}
[1, 2, 3]
[-1, -3, -2, -3, -1]
[1, 2, 3, 4, 5]
[3, 2, 7, 3, 3, 4, 1, 1, 4]
[8, 5, 1, 2, 1, 1, 2, 1, 4, 5]

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