// Private method for deleting a node. Called from the public delete method. Works recursively
// Method works by recursively deleting a node, and then once backing out of the recursion all
// data members are updated for each node
private boolean delete(TreeNode t, Point p, boolean cd) {
boolean status = false;
// Base case, not found so return false
if (t == null) return false;
if (t.p.equals(p)) { // Found the node, now delete it
if (t.right != null) {
TreeNode min = findMin(t.right, cd);
swapData(t, min);
status = delete(min, min.p, min.cd);
} else if (t.left != null) {
TreeNode min = findMin(t.left, cd);
swapData(t, min);
t.right = t.left;
t.left = null;
status = delete(min, min.p, min.cd);
} else { // At a leaf, remove the node
size--;
status = deleteFromParent(t);
}
} else if (cd) {
if (p.x() < t.p.x()) status = delete(t.left, p, !cd);
else if (p.x() > t.p.x()) status = delete(t.right, p, !cd);
else { // They must be equal, cut on y
if (p.y() < t.p.y()) status = delete(t.left, p, !cd);
else status = delete(t.right, p, !cd);
}
} else {
if (p.y() < t.p.y()) status = delete(t.left, p, !cd);
else if (p.y() > t.p.y()) status = delete(t.right, p, !cd);
else { // They must be equal, cut on x
if (p.x() < t.p.x()) status = delete(t.left, p, !cd);
else status = delete(t.right, p, !cd);
}
}
// Backing out of recursion, need to update data members
updateMinMaxOnDeleteAndRebuild(t);
t.height = maxHeight(t.left, t.right) + 1;
// Check if becoming unbalanced
if (unbalanced(t)) {
Point[] points = collectSatanSpawn(t);
TDTree newSubTree = new TDTree(points, cd);
swapDataMembers(t, newSubTree.root);
}
return status;
} // End private delete method
/**
* Private method created for inserting into the tree. Works recursively returns false if point
* already in tree Method for inserting a node into the tree. Works by traversing through the
* tree, branches off x value for even cuts, and y for odd cuts. Uses other value as a tie
* breaker. Also keeps track of height and size for constant return time on those function calls.
*/
private boolean insert(TreeNode t, TreeNode prev, TreeNode newNode, boolean cd, boolean left) {
if (t == null) { // Found where node should live
if (left) {
prev.left = newNode;
} else {
prev.right = newNode;
}
newNode.cd = cd;
newNode.parent = prev;
size++;
return true;
} else if (t.p.equals(newNode.p)) return false; // Found the point, don't insert it
// Recursive calls to left or right tree
else if (cd) {
if (newNode.p.x() < t.p.x()) insert(t.left, t, newNode, !cd, true);
else if (newNode.p.x() > t.p.x()) insert(t.right, t, newNode, !cd, false);
else { // Tie breaker
if (newNode.p.y() < t.p.y()) insert(t.left, t, newNode, !cd, true);
else insert(t.right, t, newNode, !cd, false);
}
} else {
if (newNode.p.y() < t.p.y()) insert(t.left, t, newNode, !cd, true);
else if (newNode.p.y() > t.p.y()) insert(t.right, t, newNode, !cd, false);
else { // Tie breaker
if (newNode.p.x() < t.p.x()) insert(t.left, t, newNode, !cd, true);
else insert(t.right, t, newNode, !cd, false);
}
}
updateMinMax(t, newNode);
t.height = maxHeight(t.left, t.right) + 1;
// Now check if tree became unbalanced
if (unbalanced(t)) {
// System.out.println("unbalanced");
Point[] points = collectSatanSpawn(t);
TDTree newSubTree = new TDTree(points, cd);
swapDataMembers(t, newSubTree.root);
}
return true;
} // End private insert() method
// ## operation height()
public int height() {
// #[ operation height()
return root.height();
// #]
}
