C#构建二叉查找树

 

二叉查找树的 C# 实现

 

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
6. namespace BinarySearchTree
7. {
8. publicclass Node
9. {
10. publicint Data;
11. public Node Left;
12. public Node Right;
13. publicvoid DisplayNode()
14. {
15. Console.WriteLine(Data);
16. }
17. }
20. publicclass BinarySearchTree
21. {
22. public Node root;
23. public BinarySearchTree()
24. {
25. root =null;
26. }
27. publicvoid Insert(int i)
28. {
29. Node newNode =new Node();
30. newNode.Data = i;
31. if (root ==null)
32. root = newNode;
33. else
34. {
35. Node current = root;
36. Node parent;
37. while (true)
38. {
39. parent = current;
40. if (i < current.Data)
41. {
42. current = current.Left;
43. if (current ==null)
44. {
45. parent.Left = newNode;
46. break;
47. }
48. }
49. else
50. {
51. current = current.Right;
52. if (current ==null)
53. {
54. parent.Right = newNode;
55. break;
56. }
57. }
58. }
59. }
60. }
62. publicvoid InOrder(Node theRoot)
63. {
64. if (!(theRoot ==null))
65. {
66. InOrder(theRoot.Left);
67. theRoot.DisplayNode();
68. InOrder(theRoot.Right);
69. }
70. }
72. publicint FindMax()
73. {
74. Node current = root;
75. while (!(current.Right ==null))
76. current = current.Right;
77. return current.Data;
78. }
80. public Node Find(int key)
81. {
82. Node current = root;
83. while (current.Data != key)
84. {
85. if (key < current.Data)
86. current = current.Left;
87. else
88. current = current.Right;
89. if (current ==null)
90. returnnull;
91. }
92. return current;
93. }
95. publicbool Delete(int key)
96. {
97. Node current = root;
98. Node parent = root;
99. bool isLeftChild =true;
100. while (current.Data != key)
101. {
102. parent = current;
103. if (key < current.Data)
104. {
105. isLeftChild =true;
106. current = current.Left;
107. }
108. else
109. {
110. isLeftChild = false;
111. current = current.Right;
112. }
113. if (current ==null)
114. returnfalse;
115. }
116. if ((current.Left ==null) && (current.Right == null))
117. {
118. if (current == root)
119. root =null;
120. elseif (isLeftChild)
121. parent.Left =null;
122. else
123. parent.Right =null;
124. }
125. elseif (current.Right == null)
126. if (current == root)
127. root = current.Left;
128. elseif (isLeftChild)
129. parent.Left = current.Left;
130. else
131. parent.Right = current.Left;
132. elseif (current.Left == null)
133. if (current == root)
134. root = current.Right;
135. elseif (isLeftChild)
136. parent.Left = current.Right;
137. else
138. parent.Right = current.Right;
139. else
140. {
141. Node successor = GetSuccessor(current);
142. if (current == root)
143. root = successor;
144. elseif (isLeftChild)
145. parent.Left = successor;
146. else
147. parent.Right = successor;
148. successor.Left = current.Left;
149. }
150. returntrue;
151. }
153. public Node GetSuccessor(Node delNode)
154. {
155. Node successorParent = delNode;
156. Node successor = delNode;
157. Node current = delNode.Right;
158. while (current !=null)
159. {
160. successorParent = successor;
161. successor = current;
162. current = current.Left;
163. }
164. if (successor != delNode.Right)
165. {
166. successorParent.Left = successor.Right;
167. successor.Right = delNode.Right;
168. }
169. return successor;
170. }
172. }
174. }