<?php

$khal = [100, 200, 101, 201];
$mormont = array();
$count = INF;

for($i = 0; $i < count($khal); $i++){
for ($n = 0; $n < count($khal); $n++){
	if($i==$n){
		continue;
	}
	
	$jorah = abs($khal[$i]-$khal[$n]);

	
	if($jorah < $count){
		$count = $jorah;
		$mormont[0]=$khal[$i];
		$mormont[1]=$khal[$n];
	}
}
}

var_dump ($mormont);