/// <summary>
/// 查找
/// </summary>
/// <param name="data">数据</param>
/// <param name="root">跟节点</param>
/// <returns>位置</returns>
public int search(int data, BinarySearchTreeNode root)
{
if (root == null)
{
return(-1);
}
if (data > root.data)//右子
{
return(search(data, root.right));
}
else if (data < root.data)
{
return(search(data, root.left));
}
else
{
return(root.key);
}
}
//static void Main()
//{
// BinarySearchTree bst = new BinarySearchTree();
// int[] nums = { 4, 0, 8, 1, 2, 5, 7, 6, 9 };
// for (int i = 0; i < nums.Length; i++)
// {
// bst.root= bst.insert(nums[i], i, bst.root);
// }
// bst.printTree(bst.root);
// bst.inOrder2(bst.root);
// for (int i = nums.Length - 1; i >= 0; i--)
// {
// Console.WriteLine("i=" + bst.search(nums[i] - 5, bst.root) + " num[i]=" + nums[i]);
// }
// Console.WriteLine("最大值=" + bst.getMax(bst.root));
// Console.WriteLine("最小值=" + bst.getMin(bst.root));
// Console.WriteLine("小于等于data=" + bst.getFloor(10, bst.root));
// Console.WriteLine("大于等于data=" + bst.getCell(8, bst.root));
// Console.WriteLine();
// Console.WriteLine("删除节点");
// bst.root = bst.delete(4, bst.root);
// bst.printTree(bst.root);
//}
/// <summary>
/// 插入
/// </summary>
/// <param name="data">插入的数据</param>
/// <param name="key">位置，也就是索引</param>
/// <param name="root">根节点</param>
public BinarySearchTreeNode insert(int data, int key, BinarySearchTreeNode root)
{
if (root == null)
{
Console.WriteLine("创建节点");
root = new BinarySearchTreeNode(data, key);
// return root;
}
else if (data > root.data)//找右子
{
root.right = insert(data, key, root.right);
}
else if (data < root.data)//左子
{
root.left = insert(data, key, root.left);
}
return(root);
}
/// <summary>
/// 中序遍历，非递归
/// </summary>
/// <param name="root">根节点</param>
public void inOrder2(BinarySearchTreeNode root)
{
Console.WriteLine();
Stack <BinarySearchTreeNode> s = new Stack <BinarySearchTreeNode>();
BinarySearchTreeNode t = root;
while (t != null || s.Count > 0)
{
if (t != null)
{
s.Push(t);
t = t.left;
}
else
{
t = s.Pop();
Console.WriteLine(t.data + " " + t.key);
t = t.right;
}
}
}
/// <summary>
/// 打印
/// </summary>
/// <param name="root">跟节点</param>
public void printTree(BinarySearchTreeNode root)
{
if (root == null)
{
return;
}
Queue <BinarySearchTreeNode> q = new Queue <BinarySearchTreeNode>();
BinarySearchTreeNode t = root;
q.Enqueue(t);
while (q.Count > 0)
{
t = q.Dequeue();
Console.WriteLine(t.data + " " + t.key);
if (t.left != null)
{
q.Enqueue(t.left);
}
if (t.right != null)
{
q.Enqueue(t.right);
}
}
}
/// <summary>
/// 获取删除节点的后继者
/// 删除节点的后继者是在其右节点树中最小的节点
/// </summary>
/// <param name="node">返回后继者</param>
public BinarySearchTreeNode getSon(BinarySearchTreeNode node)
{
BinarySearchTreeNode parent = node; //删除节点父节点
BinarySearchTreeNode current = node; //删除节点
BinarySearchTreeNode son = node.right; //删除节点的右节点，最后会变为后继者
Console.WriteLine(son.data);
while (son != null)
{
parent = current;
current = son;
son = son.left;
}
//Console.WriteLine(current.data);
// 检查后继者(不可能有左节点树)是否有右节点树
// 如果它有右节点树,则替换后继者位置,加到后继者父亲节点的左节点.
if (current.right != null && current != node.right)
{
parent.left = current.right;
current.right = node.right;//将要删除的节点的右子树赋值给后继者的右节点
}
return(current);
}
/// <summary>
/// 删除
/// </summary>
/// <param name="key">删除的值</param>
/// <param name="root">跟节点</param>
public BinarySearchTreeNode delete(int key, BinarySearchTreeNode root)
{
BinarySearchTreeNode parent = root; //删除节点的父节点
BinarySearchTreeNode current = root; //删除的节点
bool isLeftNode = false; //被删除节点是右节点还是左节点
//寻找被删除节点
while (current.data != key)
{
parent = current;
if (key < current.data)//左
{
isLeftNode = true;
current = current.left;
}
else if (key > current.data)//右
{
isLeftNode = false;
current = current.right;
}
if (current == null)
{
return(null);
}
}
if (current == null)//该节点不存在，返回
{
Console.WriteLine("删除失败");
return(root);
}
//该节点左右子树全为空,直接将该节点设置为空
if (current.left == null && current.right == null)
{
if (current == root)
{
root = null;
}
// 在左子树
else if (isLeftNode == true)
{
parent.left = null;
}
else
{
parent.right = null;
}
}
else if (current.left == null)//该节点左子树为空
{
Console.WriteLine("该节点左子树为空");
if (current == root)
{
root = root.right;
}
else if (isLeftNode)
{
parent.left = current.right;
}
else
{
parent.right = current.right;
}
}
else if (current.right == null)//该节点右子树为空
{
Console.WriteLine("该节点右子树为空");
if (current == root)
{
root = root.left;
}
else if (isLeftNode)
{
parent.left = current.left;
}
else
{
parent.right = current.left;
}
}
else //左右子树都不为空
{
//Console.WriteLine("左右子树都不为空");
BinarySearchTreeNode node = getSon(current);
if (current == root)
{
root = node;
//Console.WriteLine("左右子树都不为空="+node.data);
}
else if (isLeftNode)
{
parent.left = node;
}
else
{
parent.right = node;
}
//printTree(node);
//将要删除的节点的左子树赋值给后继者的左节点
node.left = current.left;
}
return(root);
}
