static int Count(ListNode head)
{
int count = 0;
while (head != null)
{
count++;
head = head.Next;
}
return count;
}
static ListNode BuildList(int[] array)
{
ListNode head = new ListNode() { Value = array[0] };
var current = head;
for (int i = 1; i < array.Length; i++)
{
current.Next = new ListNode() { Value = array[i] };
current = current.Next;
}
return head;
}
public void Add(int x)
{
count++;
if (head == null)
{
head = new ListNode(x);
tail = head;
return;
}
tail.next = new ListNode(x);
tail = tail.next;
}
private static TreeNode DoConvert(ref ListNode head, int n)
{
if (n <= 0)
{
return null;
}
TreeNode left = DoConvert(ref head, n / 2);
TreeNode root = new TreeNode() { Value = head.Value, Left = left };
head = head.Next;
root.Right = DoConvert(ref head, n - n / 2 - 1);
return root;
}
private void ShuffleRecursive(ListNode head, int size)
{
if (size <= 1)
{
return;
}
int halfSize = size / 2;
ListNode right = head;
for (int i = 0; i < halfSize; i++)
{
right = right.next;
}
ShuffleRecursive(head, halfSize);
ShuffleRecursive(right, size - halfSize);
if (ShouldFlip() || true)
{
Flip(head, halfSize, right, size - halfSize);
}
}
private void Flip(ListNode left, int leftSize, ListNode right, int rightSize)
{
ListNode leftTail = left;
ListNode rightTail = right;
//find last element on the left
for (int i = 1; i < leftSize; i++)
{
leftTail = leftTail.next;
}
//find last element on the right
for (int i = 1; i < rightSize; i++)
{
rightTail = rightTail.next;
}
ListNode temp = rightTail.next;
//last element of right points to first element of the left
rightTail.next = left;
//last element of left, points to right's old tail
leftTail.next = temp;
}
static TreeNode Convert(ListNode head)
{
int n = Count(head);
return DoConvert(ref head, n);
}