<?php $n = trim(fgets(STDIN)); $vals = explode(' ', trim(fgets(STDIN))); sort($vals); $vals = array_unique($vals); if(count($vals) > 1) { $min = array_reduce( $vals, function($ans, $item){ if(is_null($ans[0])) { $ans[0] = $item; } else { $ans[1] = min($ans[1],$item-$ans[0]); $ans[0] = $item; } return $ans; }, [null,1000000]); echo $min[1]; } else { echo 0; } echo PHP_EOL;