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package com.algorithm.study.demo.datastructure.tree;
import com.alibaba.fastjson.JSON;
import org.testng.collections.Lists;
import java.util.*;
/**
* 二叉搜索树链表存储
* 前序遍历：根节点->左子树->右子树
* 中序遍历：左子树->根节点->右子树
* 后序遍历：左子树->右子树->根节点
* Created by liuxun on 2017/6/29.
*/
public class LinkBinTree {
public static class TreeNode {
Integer data;//节点数据
TreeNode left;//左子节点数据
TreeNode right;//右子节点数据
TreeNode() {
}
TreeNode(Integer data) {
this.data = data;
this.left = null;
this.right = null;
}
public TreeNode(Integer data, TreeNode left, TreeNode right) {
this.data = data;
this.left = left;
this.right = right;
}
}
private TreeNode root;
/**
* 初始化空的二叉树
**/
public LinkBinTree() {
root = new TreeNode();
}
/**
* 指定一个默认的根二叉树
**/
public LinkBinTree(Integer d) {
root = new TreeNode(d);
}
/**
* 判断二叉树是否为空
**/
public boolean isEmpty() {
return root.data == null;
}
/**
* 获取根节点
**/
public TreeNode getRoot() {
if (isEmpty()) {
throw new RuntimeException("树为空，无法获取根节点");
}
return root;
}
/**
* 获取树的深度
**/
public int getDeep(TreeNode t) {
if (t == null) {
return 0;
}
int l = getDeep(t.left);
int r = getDeep(t.right);
return l > r ? (l + 1) : (r + 1);
}
/**
* 获取树的最小深度
**/
public int getMinDeep(TreeNode t) {
if (t == null) {
return 0;
}
if (t.left == null && t.right == null) {
return 1;
}
int l = getMinDeep(t.left);
int r = getMinDeep(t.right);
return l < r ? (l + 1) : (r + 1);
}
/**
* 获取结点数
**/
public int numOfTreeNode(TreeNode t) {
if (t == null) {
return 0;
}
int left = numOfTreeNode(t.left);
int right = numOfTreeNode(t.right);
return left + right + 1;
}
/**
* 第K层的结点数
**/
int numsOfkLevelTreeNode(TreeNode root, int k) {
if (root == null || k < 1) {
return 0;
}
if (k == 1) {
return 1;
}
int numsLeft = numsOfkLevelTreeNode(root.left, k - 1);
int numsRight = numsOfkLevelTreeNode(root.right, k - 1);
return numsLeft + numsRight;
}
private void add(TreeNode t, int value) {
if (value > t.data) {
if (t.right != null) {
add(t.right, value);
} else {
t.right = new TreeNode(value);
}
} else {
if (t.left != null) {
add(t.left, value);
} else {
t.left = new TreeNode(value);
}
}
}
private void add2(TreeNode t, int value) {
if (null == t.data) {
t.data = value;
return;
}
TreeNode node = new TreeNode(value);
TreeNode current = t;
while (true) {
TreeNode parentNode = current;
if (current.data > value) {
current = current.left;
if (current == null) {
parentNode.left = node;
return;
}
} else {
current = current.right;
if (current == null) {
parentNode.right = node;
return;
}
}
}
}
/**
* 递归从根节点开始插入数据，大于根节点放在右子树，小于根节点放在左子树
*
* @param value
*/
public void add(int value) {
add(root, value);
}
/**
* 非递归模式插入数据
* 从根节点开始插入数据，大于根节点放在右子树，小于根节点放在左子树
*
* @param value
*/
public void add2(int value) {
add2(root, value);
}
/**
* 前序遍历
* 如果树为空返回，如果不为空首先从根节点开始遍历，然后先前序遍历左子树，最后前序遍历右子树。
*/
public void preOrderTraverse(TreeNode t) {
if (t == null) {
return;
}
System.out.println(t.data);
preOrderTraverse(t.left);
preOrderTraverse(t.right);
}
public void preOrderTraverse() {
preOrderTraverse(root);
}
/**
* 非递归前序遍历
*
* @param t
*/
public void preOrderTraverse2(TreeNode t) {
if (t == null) {
return;
}
Stack<TreeNode> stack = new Stack<>();
while (t != null || !stack.isEmpty()) {
while (t != null) {
System.out.println(t.data);
stack.push(t);
t = t.left;
}
if (!stack.isEmpty()) {
t = stack.pop();
t = t.right;
}
}
}
public void preOrderTraverse2() {
preOrderTraverse2(root);
}
/**
* 中序遍历
* 如果树为空返回，从根节点开始，中序遍历左子树，然后访问根节点，最后中序遍历右子树。
*/
public void inOrderTraverse(TreeNode t) {
if (t == null) {
return;
}
inOrderTraverse(t.left);
System.out.println(t.data);
inOrderTraverse(t.right);
}
public void inOrderTraverse() {
inOrderTraverse(root);
}
/**
* 非递归中序遍历
*
* @param t
*/
public void inOrderTraverse2(TreeNode t) {
if (t == null) {
return;
}
Stack<TreeNode> stack = new Stack<>();
while (t != null || !stack.isEmpty()) {
while (t != null) {
stack.push(t);
t = t.left;
}
if (!stack.isEmpty()) {
t = stack.pop();
System.out.println(t.data);
t = t.right;
}
}
}
public void inOrderTraverse2() {
inOrderTraverse2(root);
}
/**
* 后续遍历
*
* @param t
*/
public void postOrderTraverse(TreeNode t) {
if (t == null) {
return;
}
postOrderTraverse(t.left);
postOrderTraverse(t.right);
System.out.println(t.data);
}
public void postOrderTraverse() {
postOrderTraverse(root);
}
/**
* 非递归后续遍历
*
* @param root
*/
public void postOrderTraverse2(TreeNode root) {
Stack<TreeNode> s = new Stack<TreeNode>();
Stack<Integer> s2 = new Stack<Integer>();
Integer i = new Integer(1); //0表示对应位置上的节点还没有遍历过右节点，1表示已经遍历过
while (root != null || !s.empty()) {
while (root != null) { //这个while找到最深处的左节点
s.push(root);
s2.push(new Integer(0)); //0 表示该节点的右节点还没有遍历
root = root.left;
}
while (!s.empty() && s2.peek().equals(i)) { //判断栈s最上面节点的【右节点】是否已经遍历过
s2.pop();
System.out.println(s.pop().data);
}
if (!s.empty()) { //取出s最上面的节点，遍历右节点，并将该节点的标志 从0修改成1
s2.pop();
s2.push(new Integer(1));
root = s.peek();
root = root.right;
}
}
}
public void postOrderTraverse2() {
postOrderTraverse2(root);
}
/**
* 层级遍历
*
* @param t
*/
public List<List<Integer>> divOrderTraverse(TreeNode t) {
if (t == null) {
return new ArrayList<List<Integer>>();
}
//初始化队列只包含一个节点 root 和层次编号 0 ： level = 0。
List<List<Integer>> levels = new ArrayList<>();
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.add(root);
//树的层数
int level = 0;
while (queue.size() != 0) {
//插入一个空列表，开始当前层的算法。
levels.add(new ArrayList<>());
int len = queue.size();
//计算当前层有多少个元素：等于队列的长度。
for (int i = 0; i < len; i++) {
//将这些元素从队列中弹出，并加入 levels 当前层的空列表中。
TreeNode temp = queue.poll();
levels.get(level).add(temp.data);
//将他们的孩子节点作为下一层压入队列中。
if (temp.left != null) {
queue.add(temp.left);
}
if (temp.right != null) {
queue.add(temp.right);
}
//进入下一层 level++
level++;
}
}
return levels;
}
public List<List<Integer>> levelOrder(TreeNode root) {
if (root == null) {
return new ArrayList<List<Integer>>();
}
List<List<Integer>> lists = new ArrayList<>();
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.offer(root);
while (queue.size() > 0) {
LinkedList<Integer> levelList = new LinkedList<>();
for (int i = queue.size(); i > 0; i--) {
TreeNode node = queue.poll();
if ((lists.size() & 1) == 1) {
//奇数层放到队列尾部
levelList.addLast(node.data);
} else {
//偶数层放到队列头部
levelList.addFirst(node.data);
}
if (node.right != null) {
queue.offer(node.right);
}
if (node.left != null) {
queue.offer(node.left);
}
}
lists.add(levelList);
}
return lists;
}
/**
* 层级遍历1
*/
public void divOrderTraverse() {
List<List<Integer>> lists = divOrderTraverse(root);
System.out.println(JSON.toJSONString(lists));
}
/**
* 层级遍历2
*/
public void levelOrder() {
List<List<Integer>> lists = levelOrder(root);
System.out.println(JSON.toJSONString(lists));
}
/**
* 序列化树
*
* @param root
* @return
*/
public String serialize(TreeNode root) {
if (root == null) {
return null;
}
//使用层序遍历
Queue<TreeNode> que = new LinkedList();
StringBuilder sb = new StringBuilder("[");
que.add(root);
while (que.size() > 0) {
int currSize = que.size();
for (int i = 0; i < currSize; i++) {
TreeNode node = que.poll();
if (node != null) {
sb.append(node.data).append(",");
que.add(node.left);
que.add(node.right);
} else {
sb.append("null,");
}
}
}
return sb.deleteCharAt(sb.length() - 1).append("]").toString();
}
public String serialize() {
String serialize = serialize(root);
System.out.println(serialize);
return serialize;
}
// Decodes your encoded data to tree.
public TreeNode deserialize(String data) {
if (data == null || data.length() == 0) {
return null;
}
data = data.substring(1, data.length() - 1);
String[] arrData = data.split(",");
//填充根节点
TreeNode tree = new TreeNode(Integer.valueOf(arrData[0]));
Queue<TreeNode> que = new LinkedList<>();
que.add(tree);
int i = 1;
while (que.size() > 0 && i < arrData.length) {
TreeNode currNode = que.poll();
if (arrData[i].equals("null")) {
currNode.left = null;
} else {
TreeNode treeLeft = new TreeNode(Integer.valueOf(arrData[i]));
currNode.left = treeLeft;
que.add(treeLeft);
}
i++;
if (arrData[i].equals("null")) {
currNode.right = null;
} else {
TreeNode treeRight = new TreeNode(Integer.valueOf(arrData[i]));
currNode.right = treeRight;
que.add(treeRight);
}
i++;
}
return tree;
}
/**
* 区间搜索
**/
private void searchSection(TreeNode t, int k1, int k2, ArrayList<Integer> result) {
if (t == null) {
return;
}
if (t.data > k1) {
searchSection(t.left, k1, k2, result);
}
if (t.data >= k1 && t.data <= k2) {
result.add(t.data);
}
if (t.data < k2) {
searchSection(t.right, k1, k2, result);
}
}
/**
* 二叉查找树搜索
*
* @param key
* @return
*/
public TreeNode find(int key) {
TreeNode currnode = root;
while (currnode != null) {
if (currnode.data > key) {
currnode = currnode.left;
} else if (currnode.data < key) {
currnode = currnode.right;
} else {
return currnode;
}
}
return null;
}
/**
* 查找最小值
*
* @return
*/
public TreeNode findMin() {
TreeNode current = root;
TreeNode minNode = current;
while (current != null) {
minNode = current;
current = current.left;
}
return minNode;
}
/**
* 查找最大值
*
* @return
*/
public TreeNode findMax() {
TreeNode current = root;
TreeNode maxNode = current;
while (current != null) {
maxNode = current;
current = current.right;
}
return maxNode;
}
public static void main(String[] args) {
int[] ls = new int[]{30, 9, 8, 33, 45, 11, 55, 66};
LinkBinTree linkBinTree = new LinkBinTree();
for (int i = 0; i < ls.length; i++) {
linkBinTree.add2(ls[i]);//非递归
// linkBinTree.add(ls[i]);//递归
}
System.out.println("树的深度" + linkBinTree.getDeep(linkBinTree.getRoot()));//返回指定结点的深度
System.out.println("-----------------------------");
// System.out.println("最小树的深度"+linkBinTree.getMinDeep(linkBinTree.getRoot()));//返回最小树的深度
// System.out.println("-----------------------------");
// System.out.println("节点数"+linkBinTree.numOfTreeNode(linkBinTree.getRoot()));
// System.out.println("-----------------------------");
// System.out.println("第K层的结点数"+linkBinTree.numsOfkLevelTreeNode(linkBinTree.getRoot(),4));
// System.out.println("-----------------------------");
// ArrayList<Integer> list=new ArrayList<Integer>();
// linkBinTree.searchSection(linkBinTree.getRoot(),10,20,list);
// System.out.println("区间查询"+list.toString());
System.out.println("-------------递归遍历----------------");
// linkBinTree.preOrderTraverse();//前序遍历 从根节点开始遍历
System.out.println("-----------------------------");
// linkBinTree.inOrderTraverse();//中序遍历 从根节点开始
System.out.println("-----------------------------");
// linkBinTree.postOrderTraverse();//后序遍历
System.out.println("-----------------------------");
// linkBinTree.divOrderTraverse();//层次遍历
// linkBinTree.levelOrder();
//序列化、反序列化树
System.out.println("-----------------------------");
TreeNode deserializeTree = linkBinTree.deserialize(linkBinTree.serialize());
linkBinTree.levelOrder(deserializeTree);
// //前序遍历：根节点->左子树->右子树
// //中序遍历：左子树->根节点->右子树
// //后序遍历：左子树->右子树->根节点
// System.out.println();
// System.out.println("-------------非递归遍历----------------");
// linkBinTree.preOrderTraverse2();//前序遍历
// System.out.println("-----------------------------");
// linkBinTree.inOrderTraverse2();//中序遍历
// System.out.println("-----------------------------");
// linkBinTree.postOrderTraverse2();//后序遍历
//二叉查找树搜索
// TreeNode node = linkBinTree.find(9);
// System.out.println(node.data);
// System.out.println("最小值为："+linkBinTree.findMin().data);
}
}