递归 - 查找具有最多子项的元素

Question

I have a PHP object (or it could be an array) and I want to iterate through its elements and all of its child elements recursively, and find which element has the most number of children.

This is what I have done.

var $max_element = array();

$this->find_longest_element_recursively($data, 0, array());

public function find_longest_element_recursively($object, $index, $max_array) {

  if(!is_array((array) $object) || is_string($object) || is_numeric($object) || is_bool($object)) {

  } else {
    foreach($object as $key => $element) {
      if(sizeof((array) $element) > sizeof((array) $this->max_array)) {
        $this->max_array = $element;
      }
      $this->find_longest_element_recursively($element, $index+1, $max_array);
    }
  }     
}

ok. So this works for me. But I just don't think this is the proper way of doing a recursion. I think I can get rid of that $max_element variable and return the actual max_element object as a result of the recursive function, but unsure of how to keep track of the max_element object during the recursion. Love to hear your thoughts. Thanks in advance.

Answer 1

You could enclose this in a class :

class MaxFinder {

    var $max_element = array();
    function MaxFinder() {
    }

    public function find_longest_element_recursively($object, $index, $max_array) {

      if(!is_array((array) $object) || is_string($object) || is_numeric($object) || is_bool($object)) {

      } else {
        foreach($object as $key => $element) {
          if(sizeof((array) $element) > sizeof((array) $this->max_array)) {
            $this->max_array = $element;
          }
          $this->find_longest_element_recursively($element, $index+1, $max_array);
        }
      }     
     }

     public get_longest_element($object, $index, $max_array) {
          $this->find_longest_element_recursively($object, $index, $max_array);
          return $this->max_element;
     }
}

This would offer you a one call only computation and not clutter your variable space :

 $result = (new MaxFinder()).get_longest_element_recursively($data, 0, array());

Of course you could also make a static function doing for you the instanciation and the get_... call.