Just PHP FUN 121.

encript_decript.php

<?php
# https://www.codewars.com/kata/57814d79a56c88e3e0000786 Simple Encryption #1 - Alternating Split.
function encrypt($text, $n) {
  if($n <= 0) return $text;
  if(null === $text ||  0 == strlen($text)) return $text;
  while ($n > 0){
    $text = e_step($text);
    $n -= 1;
  }
  return $text;
}

function decrypt($text, $n) {
  if($n <= 0) return $text;
  if(null === $text ||  0 == strlen($text)) return $text;
  if(null === $text ||  0 == strlen($text)) return $text;
  while ($n > 0){
    $text = d_step($text);
    $n -= 1;
  }
  return $text;

}

function e_step($str){
  $a = ""; $b = "";
  for($i = 0; $i < strlen($str); $i+=1)
    if(0 == $i % 2) $a .= $str[$i];
    else $b .= $str[$i];
  return $b.$a;
}
function d_step($str){
    $a = ""; $b = ""; $ans ="";
  for($i = 0; $i < strlen($str); $i+=1)
    if( $i < floor(strlen($str)/2) ) $b .= $str[$i];
    else $a .= $str[$i];
  for($i = 0, $j = 0; $i < strlen($a) && $j < strlen($b); $i+=1, $j+=1) $ans .= $a[$i].$b[$j];
  if($i < strlen($a)) $ans .= substr($a,$i);
  return $ans;
}

just_php_fun_121.md

Just PHP FUN 121.

• https://www.codewars.com/kata/57814d79a56c88e3e0000786 Simple Encryption #1 - Alternating Split.

Started at 23:54 06.10.2020 Tuesday Oct.
Finished at 02:36 07.10.2020 Wednesday Oct. (2rhs 42 minutes)