- array_filter: documentation ( source)
- array_unique: documentation ( source)
- json_encode: documentation ( source)
<?php
$input = ["a", "b", "c"];
function search($input)
{
$result = $input;
foreach($input as $a)
foreach($input as $b)
$result []= $a . $b;
return array_filter(array_unique($result));
}
echo json_encode(search($input));