package chap08.tree;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;class Node {public int iData;public double dData;public Node leftChild;public Node rightChild;public void displayNode() {System.out.print("{" + iData + ", " + dData + "}");}
}class Tree {// first node of treeprivate Node root; public Tree() {root = null;} /** 查找*/public Node find(int key) { // (assumes non-empty tree)Node current = root; // start at rootwhile (current.iData != key) // while no match,
        {if (key < current.iData) { current = current.leftChild;}else {current = current.rightChild;}if (current == null) {return null; }}return current; // found it
    } /** 插入*/public void insert(int id, double dd) {Node newNode = new Node(); // make new nodenewNode.iData = id; // insert datanewNode.dData = dd;if (root == null) { // no node in rootroot = newNode;}else // root occupied
        {Node current = root; // start at root
            Node parent;while (true) // (exits internally)
            {parent = current;if (id < current.iData) {current = current.leftChild;if (current == null) { // insert on leftparent.leftChild = newNode;return;}} else {current = current.rightChild;if (current == null) { // insert on rightparent.rightChild = newNode;return;}} } } } /** 删除*/public boolean delete(int key) { // (assumes non-empty list)Node current = root;Node parent = root;boolean isLeftChild = true;// search for nodewhile (current.iData != key) {parent = current;if (key < current.iData) // go left?
            {isLeftChild = true;current = current.leftChild;} else {isLeftChild = false;current = current.rightChild;}if (current == null) // end of the line,return false; // didn't find it
        } // if no children, simply delete itif (current.leftChild == null && current.rightChild == null) {if (current == root) {root = null; }else if (isLeftChild) {parent.leftChild = null; // disconnect
            }else {// from parentparent.rightChild = null;}}// if no right child, replace with left subtreeelse if (current.rightChild == null) {if (current == root) {root = current.leftChild;}else if (isLeftChild) {parent.leftChild = current.leftChild;}else {parent.rightChild = current.leftChild;}}// if no left child, replace with right subtreeelse if (current.leftChild == null)if (current == root)root = current.rightChild;else if (isLeftChild)parent.leftChild = current.rightChild;elseparent.rightChild = current.rightChild;// 有两个孩子，则用中序后继替代else {// get successor of node to delete (current)Node successor = getSuccessor(current);// connect parent of current to successor insteadif (current == root) {root = successor;}else if (isLeftChild) {parent.leftChild = successor;}else {parent.rightChild = successor;}// connect successor to current's left childsuccessor.leftChild = current.leftChild;} return true; } /** 获取后继* 返回具有倒数第二高的值的节点* 找到右孩子，然后右孩子的左子孙*/private Node getSuccessor(Node delNode) {Node successorParent = delNode;Node successor = delNode;// go to right childNode current = delNode.rightChild; while (current != null) { successorParent = successor;successor = current;// go to left childcurrent = current.leftChild; }// if successor not right childif (successor != delNode.rightChild) { // make connectionssuccessorParent.leftChild = successor.rightChild;successor.rightChild = delNode.rightChild;}return successor;}public void traverse(int traverseType) {switch (traverseType) {case 1:System.out.print("\nPreorder traversal: ");preOrder(root);break;case 2:System.out.print("\nInorder traversal:  ");inOrder(root);break;case 3:System.out.print("\nPostorder traversal: ");postOrder(root);break;}System.out.println();}/** 先序遍历*/private void preOrder(Node localRoot) {if (localRoot != null) {System.out.print(localRoot.iData + " ");preOrder(localRoot.leftChild);preOrder(localRoot.rightChild);}}/** 中序遍历*/private void inOrder(Node localRoot) {if (localRoot != null) {inOrder(localRoot.leftChild);System.out.print(localRoot.iData + " ");inOrder(localRoot.rightChild);}}/** 后序遍历*/private void postOrder(Node localRoot) {if (localRoot != null) {postOrder(localRoot.leftChild);postOrder(localRoot.rightChild);System.out.print(localRoot.iData + " ");}}/** 在控制台打印显示树 * */public void displayTree() {// 全局栈，初始放入树的根节点Stack globalStack = new Stack();globalStack.push(root);// 打印空格的数量int nBlanks = 32;// 是否为空的标识boolean isRowEmpty = false;while (isRowEmpty == false) {// 本地栈Stack localStack = new Stack();// 设置标识为空，后边再根据实际情况判断其是否不为空isRowEmpty = true;// 打印一定数量的空格，为了将节点 放置在适当的位置以满足视觉效果上树的形状for (int j = 0; j < nBlanks; j++) {System.out.print(' ');}while (globalStack.isEmpty() == false) {// 当标识不为空时，从全局栈弹出栈顶节点Node temp = (Node) globalStack.pop();if (temp != null) {// 如果当前从全局栈弹出的栈顶元素 不为空，则打印当前节点数值，同时将其左右孩子节点放入本地栈
                    System.out.print(temp.iData);// 先放左孩子，后方右孩子，后边转移到全局栈后，可以反序，从而保证左孩子在右孩子顶端
                    localStack.push(temp.leftChild);localStack.push(temp.rightChild);// 如果当前全局栈弹出的节点有左孩子或右孩子if (temp.leftChild != null || temp.rightChild != null) {// 设置标识不为空isRowEmpty = false;}} else {// 如果当前从全局栈弹出的栈顶元素 为空，则打印"--"替代节点数值，同时将两个空值放入本地栈System.out.print("-");localStack.push(null);localStack.push(null);}for (int j = 0; j < nBlanks * 2 - 1; j++) {System.out.print(' ');}} System.out.println();System.out.println();nBlanks /= 2;while (localStack.isEmpty() == false) {// 将本地栈的节点放入全局栈，进行反序，从而保证先处理左孩子
                globalStack.push(localStack.pop());}} }
} class TreeApp {public static void main(String[] args) throws IOException {int value;Tree theTree = new Tree();theTree.insert(50, 1.5);theTree.insert(25, 1.2);theTree.insert(75, 1.7);theTree.insert(12, 1.5);theTree.insert(37, 1.2);theTree.insert(43, 1.7);theTree.insert(30, 1.5);theTree.insert(33, 1.2);theTree.insert(87, 1.7);theTree.insert(93, 1.5);while (true) {System.out.print("Enter first letter of show, insert, find, delete, or traverse: ");int choice = getChar();switch (choice) {case 's':theTree.displayTree();break;case 'i':System.out.print("Enter value to insert: ");value = getInt();theTree.insert(value, value + 0.9);break;case 'f':System.out.print("Enter value to find: ");value = getInt();Node found = theTree.find(value);if (found != null) {System.out.print("Found: ");found.displayNode();System.out.print("\n");} else {System.out.print("Could not find ");}System.out.print(value + '\n');break;case 'd':System.out.print("Enter value to delete: ");value = getInt();boolean didDelete = theTree.delete(value);if (didDelete) {System.out.print("Deleted " + value + '\n');}else {System.out.print("Could not delete ");}System.out.print(value + '\n');break;case 't':System.out.print("Enter type 1, 2 or 3: ");value = getInt();theTree.traverse(value);break;default:System.out.print("Invalid entry\n");} } } /** 获取输入 */public static String getString() throws IOException {InputStreamReader isr = new InputStreamReader(System.in);BufferedReader br = new BufferedReader(isr);String s = br.readLine();return s;}public static char getChar() throws IOException {String s = getString();return s.charAt(0);}public static int getInt() throws IOException {String s = getString();return Integer.parseInt(s);}
}