对于遍历不过多的赘述，关于查找有关的思想，关键是如何实现查找的顺序以及结果的回传；附代码
1 package dataSrtuct;
2
3 public class BinaryTreeDemo {
4 public static void main(String[] args) {
5 BinaryTree binaryTree=new BinaryTree();
6 TreeNode root=new TreeNode(1,"MLQ");
7 TreeNode node1=new TreeNode(2,"ZBB");
8 TreeNode node2=new TreeNode(3,"MXP");
9 TreeNode node3=new TreeNode(4,"MYP");
10 root.setLeftNext(node1);
11 root.setRightNext(node2);
12 node2.setRightNext(node3);
13 binaryTree.setRoot(root);
14 System.out.println("遍历结果1为");
15 binaryTree.preOrder();
16 System.out.println("遍历结果2为");
17 binaryTree.infixOrder();
18 System.out.println("遍历结果3为");
19 binaryTree.postOrder();
20 System.out.println("查找结果1为");
21 System.out.println(binaryTree.preOrderSearch(3)+"查找的次数为："+TreeNode.countPre);
22 System.out.println("查找结果2为");
23 System.out.println(binaryTree.infixOrderSearch(3)+"查找的次数为："+TreeNode.countInfix);
24 System.out.println("查找结果3为");
25 System.out.println(binaryTree.postOrderSearch(3)+"查找的次数为："+TreeNode.countPost);
26 }
27
28 }
29 //二叉树
30 class BinaryTree{
31 private TreeNode root;
32
33 public TreeNode getRoot() {
34 return root;
35 }
36
37 public void setRoot(TreeNode root) {
38 this.root = root;
39 }
40 //先序遍历
41 public void preOrder(){
42 if (this.root!=null)
43 this.root.preOrder();
44 else
45 System.out.println("二叉树为空，不能遍历");
46 }
47 ///中序遍历
48 public void infixOrder(){
49 if (this.root!=null)
50 this.root.infixOrder();
51 else
52 System.out.println("二叉树为空，不能遍历");
53 }
54 //后序遍历
55 public void postOrder(){
56 if (this.root!=null)
57 this.root.postOrder();
58 else
59 System.out.println("二叉树为空，不能遍历");
60 }
61 //前、后、中序查找
62 //先序查找
63 public TreeNode preOrderSearch(int val){
64 if (this.root!=null)
65 return this.root.preOrderSearch(val);
66 else {
67 System.out.println("二叉树为空，不能遍历");
68 return null;
69 }
70 }
71 //中序查找
72 public TreeNode infixOrderSearch(int val){
73 if (this.root!=null)
74 return this.root.infixOrderSearch(val);
75 else {
76 System.out.println("二叉树为空，不能遍历");
77 return null;
78 }
79 }
80 //后序查找
81 public TreeNode postOrderSearch(int val){
82 if (this.root!=null)
83 return this.root.postOrderSearch(val);
84 else {
85 System.out.println("二叉树为空，不能遍历");
86 return null;
87 }
88
89 }
90 }
91 //树节点
92 class TreeNode{
93 private int val;
94 private String name;
95 private TreeNode leftNext;
96 private TreeNode rightNext;
97 public static int countPre;
98 public static int countInfix;
99 public static int countPost;
100 static {
101 countPre=0;
102 countInfix=0;
103 countPost=0;
104 }
105
106 public TreeNode(int val, String name) {
107 this.val = val;
108 this.name = name;
109 }
110
111 public int getVal() {
112 return val;
113 }
114
115 public void setVal(int val) {
116 this.val = val;
117 }
118
119 public String getName() {
120 return name;
121 }
122
123 public void setName(String name) {
124 this.name = name;
125 }
126
127 public TreeNode getLeftNext() {
128 return leftNext;
129 }
130
131 public void setLeftNext(TreeNode leftNext) {
132 this.leftNext = leftNext;
133 }
134
135 public TreeNode getRightNext() {
136 return rightNext;
137 }
138
139 public void setRightNext(TreeNode rightNext) {
140 this.rightNext = rightNext;
141 }
142
143 @Override
144 public String toString() {
145 return "TreeNode{" +
146 "val=" + val +
147 ", name='" + name + '\'' +
148 '}';
149 }
150 //先序查找
151 public TreeNode preOrderSearch(int val){
152 TreeNode.countPre++;
153 if (this.val==val)
154 return this;
155 TreeNode tempNode=null;
156 if (this.leftNext!=null)
157 tempNode=this.leftNext.preOrderSearch(val);
158 if (tempNode!=null)
159 return tempNode;
160 if (this.rightNext!=null)
161 tempNode= this.rightNext.preOrderSearch(val);
162 return tempNode;
163 }
164 //中序查找
165 public TreeNode infixOrderSearch(int val){
166 TreeNode.countInfix++;
167 TreeNode tempNode=null;
168 if (this.leftNext!=null)
169 tempNode=this.leftNext.infixOrderSearch(val);
170 if (tempNode!=null)
171 return tempNode;
172 if (this.val==val)
173 return this;
174 if (this.rightNext!=null)
175 tempNode=this.rightNext.infixOrderSearch(val);
176 return tempNode;
177 }
178 //后序查找
179 public TreeNode postOrderSearch(int val){
180 TreeNode.countPost++;
181 TreeNode tempNode=null;
182 if (this.leftNext!=null)
183 tempNode=this.leftNext.postOrderSearch(val);
184 if (tempNode!=null)
185 return tempNode;
186 if (this.rightNext!=null)
187 tempNode=this.rightNext.postOrderSearch(val);
188 if (tempNode!=null)
189 return tempNode;
190 if (this.val==val)
191 return this;
192 return tempNode;
193
194 }
195 //先序遍历
196 public void preOrder(){
197 System.out.println(this);
198 if (this.leftNext!=null)
199 this.leftNext.preOrder();
200 if (this.rightNext!=null)
201 this.rightNext.preOrder();
202 }
203 ///中序遍历
204 public void infixOrder(){
205 if (this.leftNext!=null)
206 this.leftNext.infixOrder();
207 System.out.println(this);
208 if (this.rightNext!=null)
209 this.rightNext.infixOrder();
210 }
211 //后序遍历
212 public void postOrder(){
213 if (this.leftNext!=null)
214 this.leftNext.postOrder();
215 if (this.rightNext!=null)
216 this.rightNext.postOrder();
217 System.out.println(this);
218 }
219 }
标签：遍历,TreeNode,val,return,二叉树,Java,null,root,public From： https://www.cnblogs.com/Mexcellent/p/17311137.html