-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathFlattenBinaryTreeToLinkedList.java
More file actions
61 lines (46 loc) · 1.52 KB
/
Copy pathFlattenBinaryTreeToLinkedList.java
File metadata and controls
61 lines (46 loc) · 1.52 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
// Given a binary tree, flatten it to a linked list in-place.
// See: https://leetcode.com/problems/flatten-binary-tree-to-linked-list/
package leetcode.tree;
import static leetcode.util.tree.BinTreeUtil.*;
import java.util.ArrayList;
import java.util.List;
import leetcode.util.tree.TreeNode;
public class FlattenBinaryTreeToLinkedList {
public void flatten(TreeNode root) {
if (root == null)
return;
flatten(root.left);
flatten(root.right);
if (root.left != null) {
TreeNode leftNode = root.left;
while (leftNode.right != null) {
leftNode = leftNode.right;
}
leftNode.right = root.right;
root.right = root.left;
root.left = null;
}
}
public void flatten1(TreeNode root) {
List<TreeNode> l = dfs(root, new ArrayList<>());
for (int i = 1; i < l.size(); i++) {
root.right = l.get(i);
root.left = null;
root = root.right;
}
}
private List<TreeNode> dfs(TreeNode root, List<TreeNode> list) {
if (root == null)
return new ArrayList<>();
list.add(root);
dfs(root.left, list);
dfs(root.right, list);
return list;
}
public static void main(String[] args) {
FlattenBinaryTreeToLinkedList sln = new FlattenBinaryTreeToLinkedList();
TreeNode root = initTree(1, 2, 5, 3, 4, 6);
sln.flatten(root);
printInorder(root);
}
}