服务器之家:专注于服务器技术及软件下载分享
分类导航

PHP教程|ASP.NET教程|Java教程|ASP教程|编程技术|正则表达式|C/C++|IOS|C#|Swift|Android|VB|R语言|JavaScript|易语言|vb.net|

服务器之家 - 编程语言 - Java教程 - Java实现的二叉树常用操作【前序建树,前中后递归非递归遍历及层序遍历】

Java实现的二叉树常用操作【前序建树,前中后递归非递归遍历及层序遍历】

2021-03-24 15:24idealemail Java教程

这篇文章主要介绍了Java实现的二叉树常用操作,包括二叉树的前序建树,前中后递归非递归遍历及层序遍历等相关操作技巧,需要的朋友可以参考下

本文实例讲述了Java实现的二叉树常用操作。分享给大家供大家参考,具体如下:

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
import java.util.ArrayDeque;
import java.util.Queue;
import java.util.Stack;
//二叉树的建树,前中后 递归非递归遍历 层序遍历
//Node节点
class Node {
    int element;
    Node left;
    Node right;
    public Node() {
    }
    public Node(int element) {
        this.element = element;
    }
}
// BinaryTree
public class Tree {
    // creat tree from array
    public static Node creatTree(int[] data, int i) {
        if (i >= data.length || data[i] == -1)
            return null;
        Node temp = new Node(data[i]);
        temp.left = creatTree(data, i * 2 + 1);
        temp.right = creatTree(data, i * 2 + 2);
        return temp;
    }
    // pre前序遍历递归
    public static void pre(Node temp) {
        if (temp == null)
            return;
        System.out.print(temp.element + " ");
        pre(temp.left);
        pre(temp.right);
    }
    // mid中序遍历递归
    public static void mid(Node temp) {
        if (temp == null)
            return;
        mid(temp.left);
        System.out.print(temp.element + " ");
        mid(temp.right);
    }
    // last后序遍历递归
    public static void last(Node temp) {
        if (temp == null)
            return;
        last(temp.left);
        last(temp.right);
        System.out.print(temp.element + " ");
    }
    // pre1前序遍历非递归
    public static void pre1(Node temp) {
        Stack<Node> stack = new Stack<>();
        while (temp != null || !stack.isEmpty()) {
            while (temp != null) {
                stack.push(temp);
                System.out.print(temp.element + " ");
                temp = temp.left;
            }
            if (!stack.isEmpty()) {
                temp = stack.pop().right;
            }
        }
    }
    // mid1中序遍历非递归
    public static void mid1(Node temp) {
        Stack<Node> stack = new Stack<>();
        while (temp != null || !stack.isEmpty()) {
            while (temp != null) {
                stack.push(temp);
                temp = temp.left;
            }
            if (!stack.isEmpty()) {
                temp = stack.pop();
                System.out.print(temp.element + " ");
                temp = temp.right;
            }
        }
    }
    // last1后序遍历非递归
    public static void last1(Node temp) {
        Stack<Node> stack = new Stack<>();
        Stack<Node> stack2 = new Stack<>();
        while (temp != null || !stack.isEmpty()) {
            while (temp != null) {
                stack.push(temp);
                stack2.push(temp);
                temp = temp.right;
            }
            if (!stack.isEmpty()) {
                temp = stack.pop().left;
            }
        }
        while (!stack2.isEmpty())
            System.out.print(stack2.pop().element + " ");
    }
    // ceng层序遍历
    public static void ceng(Node temp) {
        if (temp == null)
            return;
        Queue<Node> queue = new ArrayDeque<>();
        queue.offer(temp);
        while (!queue.isEmpty()) {
            temp = queue.poll();
            System.out.print(temp.element + " ");
            if (temp.left != null)
                queue.offer(temp.left);
            if (temp.right != null)
                queue.offer(temp.right);
        }
    }
    // Demo
    public static void main(String[] args) {
        int[] array = { 1, 2, 3, 4, 5, 6, 7, -1, -1, 10, -1, -1, 13 };
        Node tree = creatTree(array, 0);
        System.out.println("服务器之家测试结果:");
        pre(tree);
        System.out.println();
        pre1(tree);
        System.out.println();
        mid(tree);
        System.out.println();
        mid1(tree);
        System.out.println();
        last(tree);
        System.out.println();
        last1(tree);
        System.out.println();
        ceng(tree);
    }
}

运行结果:

Java实现的二叉树常用操作【前序建树,前中后递归非递归遍历及层序遍历】

希望本文所述对大家java程序设计有所帮助。

原文链接:http://blog.csdn.net/idealemail/article/details/51382114

延伸 · 阅读

精彩推荐