Just PHP FUN 020.

evaporator.php

<?php
# https://www.codewars.com/kata/5506b230a11c0aeab3000c1f Deodorant Evaporator.
function evaporator($content, $evap_per_day, $threshold) {
    $day = 0;
    $border = $content * ( $threshold/ 100);
    while($content >= $border){
      $day += 1;
      $content = $content - $content * ($evap_per_day/100);
    }
    return $day;
}

just_php_fun_020.md

Just PHP FUN 020.

• https://www.codewars.com/kata/5d376cdc9bcee7001fcb84c0 Odd Ones Out!
• https://www.codewars.com/kata/5cd12646cf44af0020c727dd Square Pi's.
• https://www.codewars.com/kata/5506b230a11c0aeab3000c1f Deodorant Evaporator.
• https://www.codewars.com/kata/5500d54c2ebe0a8e8a0003fd Greatest common divisor.
• https://www.codewars.com/kata/56d5166ec87df55dbe000063 Sum of Array Averages.

Started at 20:49 10.06.2020 Wednesday June.
Finised at 23:28 10.06.2020 Wednesday June. (2hrs 39minutes)

mygcd.php

<?php
# https://www.codewars.com/kata/5500d54c2ebe0a8e8a0003fd Greatest common divisor.
function mygcd($x, $y) {
  echo "Input $x and $y \n";
  $max = max($x,$y);
  $min = min($x,$y);
  return g($max,$min);
  # https://youtu.be/JUzYl1TYMcU
}
function g($max, $min){
  # max = min * (max/min) + max%min
  $r = $max % $min;
  echo "$max = $min * ".intval($max/$min)." + $r \n";
  if(0 == $r) return $min;
  return g($min,$r);
}

odd_ones_out.php

<?php
# https://www.codewars.com/kata/5d376cdc9bcee7001fcb84c0 Odd Ones Out!
function odd_ones_out($arr) {
  $hist = array_count_values($arr);
  $rmv = function($x) use ($hist){ return 0 == $hist[$x]%2; };
  return array_values(array_filter($arr,$rmv));
}
# ---------------------------------------------------------------------
function odd_ones_out($arr) {
  $hist = [];
  foreach($arr as $x){
    if(!isset($hist[$x])) $hist[$x] = 0;
    $hist[$x] += 1;
  }
  $remove_oddes = function($x) use ($hist){
    return  0 == $hist[$x]%2;
  };
  return array_values(array_filter($arr,$remove_oddes));
}

squarePi.php

<?php
# https://www.codewars.com/kata/5cd12646cf44af0020c727dd Square Pi's.
function squarePi($digits){
  $row = "31415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679";
  $arr = str_split($row);
  for($i = 0, $prev = 0; $i < count($arr); $i +=1 ){
    $arr[$i] = pow($arr[$i],2) + $prev;
    $prev = $arr[$i];
  }
  $arr = array_map('sqrt',$arr);
  $arr = array_map('ceil',$arr);
  return $arr[$digits-1];
}

sumAverage.php

<?php
# https://www.codewars.com/kata/56d5166ec87df55dbe000063 Sum of Array Averages.
function sumAverage($arr) {
  $avg = function($x){ return array_sum($x)/count($x);};
  return floor(array_sum(array_map($avg,$arr)));
}