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3294. Convert Doubly Linked List to Array II

  • Time: $O(n)$
  • Space: $O(n)$
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class Solution {
 public:
  vector<int> toArray(Node* node) {
    vector<int> ans;
    Node* curr = node;

    while (curr->prev != nullptr)
      curr = curr->prev;

    while (curr != nullptr) {
      ans.push_back(curr->val);
      curr = curr->next;
    }

    return ans;
  }
};

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class Solution {
  public int[] toArray(Node node) {
    List<Integer> ans = new ArrayList<>();
    Node curr = node;

    while (curr.prev != null)
      curr = curr.prev;

    while (curr != null) {
      ans.add(curr.val);
      curr = curr.next;
    }

    return ans.stream().mapToInt(Integer::intValue).toArray();
  }
}

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class Solution:
  def toArray(self, node: 'Optional[Node]') -> list[int]:
    ans = []
    curr = node

    while curr.prev:
      curr = curr.prev

    while curr:
      ans.append(curr.val)
      curr = curr.next

    return ans