protected override IEnumerable <T> PreOrderTraversal() { if (Head != null) { var stack = new Stack <BinarySearchTreeNode <T> >(); BinarySearchTreeNode <T> current = Head; bool goLeftNext = true; stack.Push(current); yield return(current.Value); while (stack.Count > 0) { if (goLeftNext) { while (current.Left != null) { stack.Push(current); current = current.Left; yield return(current.Value); } } if (current.Right != null) { current = current.Right; goLeftNext = true; yield return(current.Value); } else { current = stack.Pop(); goLeftNext = false; } } } }
public override sealed void Add(T value) { if (Head == null) { Head = new BinarySearchTreeNode <T>(value); } else { BinarySearchTreeNode <T> current = Head; while (true) { if (value.CompareTo(current.Value) < 0) { if (current.Left == null) { current.Left = new BinarySearchTreeNode <T>(value); break; } current = current.Left; } else { if (current.Right == null) { current.Right = new BinarySearchTreeNode <T>(value); break; } current = current.Right; } } } Count++; }
public override sealed bool Remove(T value) { BinarySearchTreeNode <T> parent; BinarySearchTreeNode <T> current = FindWithParent(value, out parent); if (current == null) { return(false); } Count--; if (current.Right == null) { if (parent == null) { Head = current.Left; } else { int compareResult = parent.CompareTo(current.Value); if (compareResult > 0) { parent.Left = current.Left; } else if (compareResult < 0) { parent.Right = current.Left; } } } else if (current.Right.Left == null) { current.Right.Left = current.Left; if (parent == null) { Head = current.Right; } else { int compareResult = parent.CompareTo(current.Value); if (compareResult > 0) { parent.Left = current.Right; } else if (compareResult < 0) { parent.Right = current.Right; } } } else { BinarySearchTreeNode <T> leftmost = current.Right.Left; BinarySearchTreeNode <T> leftmostParent = current.Right; while (leftmost.Left != null) { leftmostParent = leftmost; leftmost = leftmost.Left; } leftmostParent.Left = leftmost.Right; leftmost.Left = current.Left; leftmost.Right = current.Right; if (parent == null) { Head = leftmost; } else { int compareResult = parent.CompareTo(current.Value); if (compareResult > 0) { parent.Left = leftmost; } else if (compareResult < 0) { parent.Right = leftmost; } } } return(true); }
public override sealed void Clear() { Head = null; Count = 0; }