-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathStack94.java
More file actions
84 lines (78 loc) · 2.3 KB
/
Stack94.java
File metadata and controls
84 lines (78 loc) · 2.3 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
package stack;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
public class Stack94 {
public List<Integer> inorderTraversal2(TreeNode root) {
List<Integer> list = new ArrayList<>();
Stack<TreeNode> stack = new Stack<>();
stack.push(root);
while (!stack.isEmpty()){
//出栈
TreeNode treeNode = stack.pop();
//判空
if (treeNode == null) {
continue;
}
// 判断叶子节点
if (treeNode.left == null && treeNode.right == null) {
list.add(treeNode.val);
continue;
}
//右节点入栈
if (treeNode.right != null) {
stack.push(treeNode.right);
treeNode.right = null;
stack.push(treeNode);
continue;
}
TreeNode left = treeNode.left;
//中间节点入栈
treeNode.left = null;
stack.push(treeNode);
//左节点入栈
if (left != null) {
stack.push(left);
continue;
}
}
return list;
}
public List<Integer> inorderTraversal(TreeNode root) {
List<Integer> list = new ArrayList<>();
Stack<TreeNode> stack = new Stack<>();
stack.push(root);
while (!stack.isEmpty()){
//出栈
TreeNode treeNode = stack.pop();
//判空
if (treeNode == null) {
continue;
}
//右节点入栈
if (treeNode.right != null) {
stack.push(treeNode.right);
treeNode.right = null;
stack.push(treeNode);
continue;
}
if (treeNode.left != null) {
TreeNode left = treeNode.left;
treeNode.left = null;
//中间节点入栈
stack.push(treeNode);
//左节点入栈
stack.push(left);
continue;
}
list.add(treeNode.val);
}
return list;
}
static class TreeNode {
int val;
TreeNode left;
TreeNode right;
TreeNode(int x) { val = x; }
}
}