Codingame CodevsZombie PHP

<?php
/**
 * Save humans, destroy zombies!
 **/


// game loop
while (TRUE)
{
    unset($human);
    unset($zombie);
    $human;
    $zombie;
    fscanf(STDIN, "%d %d", $x, $y);
    fscanf(STDIN, "%d", $humanCount);
    for ($i = 0; $i < $humanCount; $i++)
    {
        fscanf(STDIN, "%d %d %d", $humanId, $humanX, $humanY);
        $human[$i] = [
            'id'    => $humanId,
            'x'     => $humanX,
            'y'     => $humanY
        ];
    }
    fscanf(STDIN, "%d", $zombieCount);
    for ($i = 0; $i < $zombieCount; $i++)
    {
        fscanf(STDIN, "%d %d %d %d %d", $zombieId, $zombieX, $zombieY, $zombieXNext, $zombieYNext);
        $zombie[$zombieId] = [
            'id'    => $zombieId,
            'x'     => $zombieX,
            'y'     => $zombieY,
            'xn'    => $zombieXNext,
            'yn'    => $zombieYNext
        ];
    }

    // Write an action using echo(). DON'T FORGET THE TRAILING \n
    // To debug: error_log(var_export($var, true)); (equivalent to var_dump)
    $me = ['x' => $x, 'y' => $y];
    $dst = closest($human, $zombie, $me);
    $targetId = $dst[array_key_first($dst)]['zid'];
    error_log(var_export($dst, true));
    echo(round($zombie[$targetId]['x'])." ".round($zombie[$targetId]['y'])."\n"); // Your destination coordinates
    unset($targetId);

    //}
}

function closest($human, $zombie, $me)
{
    $i = 0;
    foreach($zombie as $z){
        foreach($human as $h){
            if((getDistance($me['x'], $me['y'], $h['x'], $h['y'])) -getDistance($z['x'], $z['y'], $h['x'], $h['y']) < 100 && (getDistance($me['x'], $me['y'], $h['x'], $h['y'])) -getDistance($z['x'], $z['y'], $h['x'], $h['y']) < 50 || getDistance($z['x'], $z['y'], $h['x'], $h['y']) > 40){
            $dst[$i] = [
                'hid' => $h['id'],
                'zid' => $z['id'],
                'medst' => getDistance($me['x'], $me['y'], $h['x'], $h['y']),
                'dst' => getDistance($z['x'], $z['y'], $h['x'], $h['y'])];
            $i++;
            }
        }
    }
    usort($dst, function($a, $b) {
    return $a['dst'] <=> $b['dst'];
});
    return $dst;
}


function getDistance($lat1, $lon1, $lat2, $lon2) {
    if($lat1 > $lat2){
    $xC = $lat1-$lat2;
    }elseif($lat1 == $lat2){
    $xC=0;
    }else{
    $xC = $lat2-$lat1;
    }
    if($lon1 > $lon2){
    $yC = $lon1-$lon2;
    }elseif($lon1 == $lon2){
    $yC=0;
    }else{
    $yC = $lon2-$lon1;
    }

return sqrt(($xC^2)+($yC^2));
}
?>