Project Euler Problem 25

by michiganfootball20

HTML

<html>
<head>
<title>Online PHP Script Execution</title>
</head>
<body>
<?php
   
   function largeSum($arr1,$arr2){
     $ans = array();
     $longer = max(count($arr1),count($arr2));
     for($i = 0; $i < $longer; $i++){
      $val1 = (array_key_exists($i,$arr1)) ? $arr1[$i] : 0;
      $val2 = (array_key_exists($i,$arr2)) ? $arr2[$i] : 0;
      $ans[$i] = (array_key_exists($i,$ans)) ? $ans[$i] + $val1 + $val2 : $val1 + $val2;
      if($ans[$i] > 9) {$ans[$i] = $ans[$i] - 10; $ans[$i+1] = (array_key_exists($i+1,$ans)) ?  $ans[$i+1]+1 : 1;}
     }
     return $ans;
   }
   
   $one_back = array(1);
   $two_back = array(1);
   $cur = largeSum($one_back,$two_back);
   $count = 2;
   while(count($cur) < 700){
     $cur = largeSum($one_back,$two_back);
     $two_back = $one_back;
     $one_back = $cur;
     $count++;
   }
   
   echo $count;

?>
</body>
</html>