Just PHP FUN 003.

area.php

<?php
# https://www.codewars.com/kata/580a0347430590220e000091 Find the area of the rectangle!
function area($diagonal, $side) {
  if($diagonal <= $side) return "Not a rectangle";
  return round($side * sqrt(pow($diagonal,2) - pow($side,2)),2);
}

findMiddle.php

<?php
# https://www.codewars.com/kata/5ac54bcbb925d9b437000001 Find the Middle of the Product.
function findMiddle($str){
  if(!is_string($str)){
    echo "Got it!\n";
    return -1;
  }
  echo "Hi: $str\n";
  var_dump($str);
  $str = preg_replace('/[^0-9]/',"",$str);
  var_dump($str);
  if(empty($str)) return -1;
  $str = strval(array_reduce(  
    str_split($str),
    function($acc,$v){ return $acc * $v;},
    1
  ));
  $size = strlen($str);
  if(1 == $size%2) return substr($str, floor($size/2), 1);
  $str = substr($str, $size/2-1, 2);
  return preg_replace('/^0/',"",$str);
}

in_asc_order.php

<?php
# https://www.codewars.com/kata/56b7f2f3f18876033f000307 Are the numbers in order?
function in_asc_order($arr) {
  for($i = 1; $i < count($arr); $i  += 1)
    if($arr[$i-1] > $arr[$i]) return false;
  return true;
}

just_php_fun_003.md

Just PHP FUN 003.

• https://www.codewars.com/kata/5413759479ba273f8100003d esreveR.
• https://www.codewars.com/kata/5d49c93d089c6e000ff8428c Computer problem series #1: Fill the Hard Disk Drive.
• https://www.codewars.com/kata/5ac54bcbb925d9b437000001 Find the Middle of the Product.
• https://www.codewars.com/kata/56b7f2f3f18876033f000307 Are the numbers in order?
• https://www.codewars.com/kata/580a0347430590220e000091 Find the area of the rectangle!

Started at 21.05.2020 Thursday May 19:14.
Finished at 21.05.2020 Thursday May 20:40. Total 1hr 26min.

reverse.php

<?php
# https://www.codewars.com/kata/5413759479ba273f8100003d esreveR.
function reverse(array $a): array {
  for($i=0,$j=count($a)-1; $i < $j; $i += 1, $j -=1){
     list($a[$i],$a[$j]) = [$a[$j],$a[$i]];
   }
   return $a;
}

reverseList.php

<?php
/*
 206. Reverse Linked List.
 https://leetcode.com/problems/reverse-linked-list/
Runtime: 8 ms, faster than 70.00% of PHP online submissions for Reverse Linked List.
Memory Usage: 16.6 MB, less than 50.00% of PHP online submissions for Reverse Linked Li
*/   
/**
 * Definition for a singly-linked list.
 * class ListNode {
 *     public $val = 0;
 *     public $next = null;
 *     function __construct($val = 0, $next = null) {
 *         $this->val = $val;
 *         $this->next = $next;
 *     }
 * }
 */
class Solution {

    /**
     * @param ListNode $head
     * @return ListNode
     */
    function reverseList($head) {
        $tmp = null;
        $prv = null;
        while($head){
            $tmp = $head->next;
            $head->next = $prv;
            $prv = $head;
            $head = $tmp;
        }
        return $prv;
    }
}

save.php

<?php
# https://www.codewars.com/kata/5d49c93d089c6e000ff8428c Computer problem series #1: Fill the Hard Disk Drive.
function save($sizes, $hd) {
  $sum = 0; $count = 0;
  foreach($sizes as $size){
    $sum += $size;
    if($hd < $sum) return $count;
    $count += 1;
  }
  return $count;
}