Convert Doubly Linked List to Array I
<p>You are given the <code>head</code> of a <strong>doubly linked list</strong>, which contains nodes that have a next pointer and a previous pointer.</p>

<p>Return an integer array which contains the elements of the linked list <strong>in order</strong>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">head = [1,2,3,4,3,2,1]</span></p>

<p><strong>Output:</strong> <span class="example-io">[1,2,3,4,3,2,1]</span></p>
</div>

<p><strong class="example">Example 2:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">head = [2,2,2,2,2]</span></p>

<p><strong>Output:</strong> <span class="example-io">[2,2,2,2,2]</span></p>
</div>

<p><strong class="example">Example 3:</strong></p>

<div class="example-block">
<p><strong>Input:</strong> <span class="example-io">head = [3,2,3,2,3,2]</span></p>

<p><strong>Output:</strong> <span class="example-io">[3,2,3,2,3,2]</span></p>
</div>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li>The number of nodes in the given list is in the range <code>[1, 50]</code>.</li>
	<li><code>1 &lt;= Node.val &lt;= 50</code></li>
</ul>
Array; Linked List; Doubly-Linked List
"""
# Definition for a Node.
class Node:
    def __init__(self, val, prev=None, next=None):
        self.val = val
        self.prev = prev
        self.next = next
"""


class Solution:
    def toArray(self, root: "Optional[Node]") -> List[int]:
        ans = []
        while root:
            ans.append(root.val)
            root = root.next
        return ans
