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FlattenMultilevelDoublyLinkedList
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FlattenMultilevelDoublyLinkedList
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/*
// Definition for a Node.
public class Node {
public int val;
public Node prev;
public Node next;
public Node child;
}
*/
public class Solution {
public Node Flatten(Node head)
{
if (head == null) return head;
Stack<Node> stack = new Stack<Node>();
Node currentNode = head;
while(currentNode != null)
{
if(currentNode.child != null)
{
if(currentNode.next != null)
stack.Push(currentNode.next);
currentNode.next = currentNode.child;
if (currentNode.next != null)
currentNode.next.prev = currentNode;
currentNode.child = null;
}
else if (currentNode.next == null && stack.Count != 0)
{
currentNode.next = stack.Pop();
if (currentNode.next != null)
currentNode.next.prev = currentNode;
}
currentNode = currentNode.next;
}
return head;
}
}