Php script for array exercises - php

Question

I'm trying to resolve [This exercise][1]...
I'm writing the follow code:
$steps=8;
$path=['U','D','D','D','U','D','U','U'];
function countingValleys($steps, $path) {
// Write your code here
$sea=0;
$valley=0;
$key=0;
function check($steps, $path,$valley,$key,$sea){
($path[$key]=='D')?$sea--:$sea++;
if($sea<0) $valley++;
while($sea<0){
$key++;
if($key==$steps) return $valley; else ($path[$key]=='D')?$sea--:$sea++;
}
$key++;
if($key==$steps) return $valley; else check($steps, $path,$valley,$key,$sea);
}
$Return=check($steps, $path,$valley,$key,$sea);
return $Return;
}
$Return=countingValleys($steps, $path);
echo $Return;
suddenly it returns an empty string instead the result it should... Can you help me?
Thanks
[1]: https://www.hackerrank.com/challenges/counting-valleys/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=warmup

Answer 1

It's empty string because $Return=countingValleys($steps, $path); takes null value.
The reason is that in check() method you return $valley or you call recursively check() but you also have to return it otherwise the method act like it's void method.
<?php
$steps = 8;
$path = ['U', 'D', 'D', 'D', 'U', 'D', 'U', 'U'];
function countingValleys($steps, $path)
{
// Write your code here
$sea = 0;
$valley = 0;
$key = 0;
function check($steps, $path, $valley, $key, $sea)
{
($path[$key] == 'D') ? $sea-- : $sea++;
if ($sea < 0) $valley++;
while ($sea < 0) {
$key++;
if ($key == $steps) return $valley; else ($path[$key] == 'D') ? $sea-- : $sea++;
}
$key++;
if ($key == $steps) return $valley; else return check($steps, $path, $valley, $key, $sea);
}
$Return = check($steps, $path, $valley, $key, $sea);
return $Return;
}
$Return = countingValleys($steps, $path);
echo $Return;
// output 1