Memoized Fibonacci and Factorial in PHP. Test: https://repl.it/repls/HilariousImpishProgrammingtool

MemoizedFibAndFact.php

<?php 

function factorial($number, $memoize = array(0,1)) {
  if ($number == 0 || $number == 1) {
    return 1;
  }
  
  if (!array_key_exists($number, $memoize)) {
    $memoize[$number] = $number * factorial($number-1, $memoize);
  }
  
  return $memoize[$number];
}

function fibonacci ($number, $memoize = array(0,1)) {
    if ($number == 0) {
      return 0;
    } else if ($number == 1 || $number == 2) {
      return 1;
    } else {
      if (!array_key_exists($number, $memoize)) {
        $memoize[$number] = fibonacci($number-1) + fibonacci($number-2);
      } 
      
      return $memoize[$number];
    }
}

echo "Factorial of 6: ".factorial(6)."\n";
echo "Fibonacci of 7: ".fibonacci(7)."\n";

?>