protected BSTVertex delete(BSTVertex T, int v) { if (T == null) return T; // cannot find the item to be deleted if (T.key == v) { // this is the node to be deleted if (T.left == null && T.right == null) // this is a leaf T = null; // simply erase this node else if (T.left == null && T.right != null) { // only one child at right BSTVertex temp = T; T.right.parent = T.parent; T = T.right; // bypass T temp = null; } else if (T.left != null && T.right == null) { // only one child at left BSTVertex temp = T; T.left.parent = T.parent; T = T.left; // bypass T temp = null; } else { // has two children, find successor int successorV = successor(v); T.key = successorV; // replace this key with the successor's key T.right = delete(T.right, successorV); // delete the old successorV } } else if (T.key < v) // search to the right T.right = delete(T.right, v); else // search to the left T.left = delete(T.left, v); return T; // return the updated BST }
@Override protected BSTVertex delete(BSTVertex T, Name v) { if (T == null) return T; // cannot find the item to be deleted if (T.key.babyName.equals(v.babyName)) { // this is the node to be deleted if (T.left == null && T.right == null) { // this is a leaf T = null; // simply erase this node } else if (T.left == null && T.right != null) { // only one child at right T.right.parent = T.parent; T = T.right; // bypass T } else if (T.left != null && T.right == null) { // only one child at left T.left.parent = T.parent; T = T.left; // bypass T } else { // has two children, find successor Name successorV = successor(v); T.key = successorV; // replace this key with the successor's key T.right = delete(T.right, successorV); // delete the old successorV } } else if (T.key.babyName.compareTo(v.babyName) < 0) { // search to the right T.right = delete(T.right, v); } else { // search to the left T.left = delete(T.left, v); } updateHeight(T); updateSize(T); // Balance the tree after deletion T = balance(T); return T; // return the updated BST }
protected BSTVertex insert(BSTVertex T, int v) { if (T == null) return new BSTVertex(v); // insertion point is found if (T.key < v) { // search to the right T.right = insert(T.right, v); T.right.parent = T; } else { // search to the left T.left = insert(T.left, v); T.left.parent = T; } return T; // return the updated BST }
protected BSTVertex insert(BSTVertex T, Name v) { if (T == null) return new BSTVertex(v); // insertion point is found if (T.key.babyName.compareTo(v.babyName) < 0) { // search to the right T.right = insert(T.right, v); T.right.parent = T; } else { // search to the left T.left = insert(T.left, v); T.left.parent = T; } T.height = 1 + Math.max(getHeight(T.left), getHeight(T.right)); return T; // return the updated BST }
public BSTVertex balance(BSTVertex T) { // Check the balance factor if (getBalanceFactor(T) == 2 && getBalanceFactor(T.left) == 1) { T = rotateRight(T); } else if (getBalanceFactor(T) == 2 && getBalanceFactor(T.left) == -1) { T.left = rotateLeft(T.left); T = rotateRight(T); } else if (getBalanceFactor(T) == -2 && getBalanceFactor(T.right) == 1) { T.right = rotateRight(T.right); T = rotateLeft(T); } else if (getBalanceFactor(T) == -2 && getBalanceFactor(T.right) == -1) { T = rotateLeft(T); } else {; // No need to do anything } return T; }
@Override protected BSTVertex insert(BSTVertex T, Name v) { if (T == null) return new BSTVertex(v); // insertion point is found if (T.key.babyName.compareTo(v.babyName) < 0) { // search to the right T.right = insert(T.right, v); T.right.parent = T; } else { // search to the left T.left = insert(T.left, v); T.left.parent = T; } updateHeight(T); T.size++; // Balance the tree after insertion T = balance(T); return T; // return the updated BST }
private BSTVertex rotateLeft(BSTVertex T) { BSTVertex w = T.right; // Connect the right node of T (which is w) to the parent of T w.parent = T.parent; // Put w above T T.parent = w; // Left node of w is shifted to right of T to replace w T.right = w.left; // Need to set the parent of w.left unless w.left does not exist if (w.left != null) { w.left.parent = T; } // Set T, which is under w, to w.left w.left = T; if (w.parent != null) { if (w.parent.left == T) { w.parent.left = w; } else { w.parent.right = w; } } updateHeight(T); updateHeight(w); // Only T and w has new sizes w.size = T.size; T.size = getSize(T.left) + getSize(T.right) + 1; return w; }
private BSTVertex rotateRight(BSTVertex T) { BSTVertex w = T.left; w.parent = T.parent; T.parent = w; T.left = w.right; if (w.right != null) { w.right.parent = T; } w.right = T; if (w.parent != null) { if (w.parent.left == T) { w.parent.left = w; } else { w.parent.right = w; } } updateHeight(T); updateHeight(w); w.size = T.size; T.size = getSize(T.left) + getSize(T.right) + 1; return w; }
protected void updateSize(BSTVertex T) { if (T != null) { T.size = 1 + getSize(T.left) + getSize(T.right); } }
protected void updateHeight(BSTVertex T) { if (T != null) { T.height = 1 + Math.max(getHeight(T.left), getHeight(T.right)); } }