-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathTreeTraversal.java
More file actions
171 lines (162 loc) · 5.52 KB
/
TreeTraversal.java
File metadata and controls
171 lines (162 loc) · 5.52 KB
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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
package BinarySearchTree;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Stack;
public class TreeTraversal {
private void printUtil(List<Integer> list, String traversalType) {
System.out.println("Binary Search Tree Iterative " + traversalType + " Traversal");
for (int d : list) {
System.out.print(d + " ");
}
System.out.println();
}
public void inorderTraversal(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
Stack<TreeNode> stack = new Stack<TreeNode>();
TreeNode runner = root;
while (runner != null || !stack.isEmpty()) {
if (runner != null) {
stack.push(runner);
runner = runner.left;
}
else {
TreeNode top = stack.pop();
list.add(top.key);
runner = top.right;
}
}
printUtil(list, "Inorder");
}
public void preorderTraversal(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
Stack<TreeNode> stack = new Stack<TreeNode>();
TreeNode runner = root;
while (runner != null || !stack.isEmpty()) {
if (runner != null) {
list.add(runner.key);
if (runner.right != null) {
stack.add(runner.right);
}
runner = runner.left;
}
else {
runner = stack.pop();
}
}
printUtil(list, "Preorder");
}
public void postorderTraversal(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
Stack<TreeNode> stack = new Stack<TreeNode>();
TreeNode runner = root, pre = null;
while (runner != null || !stack.isEmpty()) {
if (runner != null) {
stack.push(runner);
runner = runner.left;
}
else {
TreeNode top = stack.peek();
if (top.right == null || top.right == pre) {
list.add(top.key);
pre = stack.pop();
}
else {
runner = top.right;
}
}
}
printUtil(list, "Postorder");
}
/**
* Traversal using treaded tree: non-recursive, no-stack
*/
public void inorderWithTreadedTree(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
TreeNode runner = root;
while (runner != null) {
if (runner.left == null) {
list.add(runner.key);
runner = runner.right;
}
else {
TreeNode pre = runner.left;
while (pre.right != null && pre.right != runner) {
pre = pre.right;
}
if (pre.right == null) {
pre.right = runner;
runner = runner.left;
}
else {
list.add(runner.key);
runner = runner.right;
pre.right = null;
}
}
}
printUtil(list, "Inorder Morris Traversal Using Treaded Tree");
}
public void preorderWithThreadedTree(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
TreeNode runner = root;
while (runner != null) {
if (runner.left == null) {
list.add(runner.key);
runner = runner.right;
}
else {
TreeNode pre = runner.left;
while (pre.right != null && pre.right != runner) {
pre = pre.right;
}
if (pre.right == null) {
list.add(runner.key);
pre.right = runner;
runner = runner.left;
}
else {
pre.right = null;
runner = runner.right;
}
}
}
printUtil(list, "Preorder Morris Traversal Using Treaded Tree");
}
public void postorderWithTreadedTree(TreeNode root) {
List<Integer> list = new ArrayList<Integer>();
TreeNode dummy = new TreeNode(0);
dummy.left = root;
TreeNode runner = dummy;
while (runner != null) {
if (runner.left == null) {
runner = runner.right;
}
else {
TreeNode pre = runner.left;
while (pre.right != null && pre.right != runner) {
pre = pre.right;
}
if (pre.right == null) {
pre.right = runner;
runner = runner.left;
}
else {
List<Integer> subList = new ArrayList<Integer>();
TreeNode temp = runner.left;
while (temp != pre) {
subList.add(temp.key);
temp = temp.right;
}
subList.add(temp.key);
Collections.reverse(subList);
list.addAll(subList);
pre.right = null;
runner = runner.right;
}
}
}
dummy.left = null;
printUtil(list, "Postorder Morris Traversal Using Treaded Tree");
}
}