internal static void RemoveNode(AVLNode node, AVLTree <TKey, TValue> tree)
{
if (node.right == null && node.left == null) // no children
{
if (node.head == null) // was the top node
{
tree.head = null;
}
else
{
if (node.isLeft)
{
node.head.left = null;
node.head._depthL = 0;
}
else
{
node.head.right = null;
node.head._depthR = 0;
}
AVLNode.BalanceSelfBubbleUp(node.head, tree);
}
}
else if (node.right == null || node.left == null) // one child
{
AVLNode child = node.right != null ? node.right : node.left;
if (node.head == null) // was the top node
{
tree.head = child;
child.head = null;
}
else
{
child.isLeft = node.isLeft;
if (node.isLeft)
{
node.head.left = child;
child.head = node.head;
node.head._depthL -= 1;
}
else
{
node.head.right = child;
child.head = node.head;
node.head._depthR -= 1;
}
AVLNode.BalanceSelfBubbleUp(node.head, tree);
}
}
else // two children :O
{
AVLNode child = node.right, childhead = node.head;
while (child.left != null)
{
childhead = child;
child = child.left;
}
if (childhead != node.head)
{
if (child.right != null)
{
childhead.left = child.right;
child.right.head = childhead;
child.right.isLeft = true;
childhead._depthL--;
}
else
{
childhead.left = null;
childhead._depthL = 0;
}
child.right = node.right;
}
child.left = node.left;
child.left.head = child;
child.head = node.head;
child.isLeft = node.isLeft;
if (node.head == null)
{
tree.head = child;
}
else
{
if (node.isLeft)
{
node.head.left = child;
}
else
{
node.head.right = child;
}
}
if (childhead == node.head)
{
AVLNode.BalanceSelfBubbleUp(child, tree);
}
else
{
child.right.head = child;
AVLNode.BalanceSelfBubbleUp(childhead, tree);
}
}
tree.count--;
}
private void Rebalance(AVLTree <TKey, TValue> tree)
{
if (Math.Abs(balance) > 2)
{
if (balance < -2)
{
left.Rebalance(tree);
}
else
{
right.Rebalance(tree);
}
}
if (balance > 1)
{
// 5_2 | 7
// 2 7_1 | 5 8
// 6 8_1 | 2 6 9
// 9 |
// 5 | 5
// 2 6 | 3 6
// 3 | 2 4
// 4 |
// 5 | 5 | 7
// 2 8 | 2 7 | 5 8
// 7 9 | 6 8 | 2 6 9
// 6 | 9 |
if (right.balance > 0)
{
RotateLeft(right, tree);
}
else
{
RotateRight(right.left, tree);
RotateLeft(right, tree);
}
}
else if (balance < -1)
{
// 5 | 5
// 4 9 | 4 8
// 8 | 7 9
// 7 |
// 5 | 5 | 3
// 1 6 | 3 6 | 1 5
// 0 3 | 1 4 | 0 4 6
// 4 | 0 |
if (left.balance < 0)
{
RotateRight(left, tree);
}
else
{
RotateLeft(left.right, tree);
RotateRight(left, tree);
}
}
#if TEST
checkNodeSelf(this);
#endif
}
