-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathbinaryTreeLevelOrderTraversal.java
More file actions
38 lines (33 loc) · 1.19 KB
/
binaryTreeLevelOrderTraversal.java
File metadata and controls
38 lines (33 loc) · 1.19 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
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
public ArrayList<ArrayList<Integer>> levelOrder(TreeNode root) {
// Start typing your Java solution below
// DO NOT write main() function
ArrayList<ArrayList<Integer>> res = new ArrayList<ArrayList<Integer>>();
if(root == null) return res;
Queue<TreeNode> currLevel = new LinkedList<TreeNode>();
Queue<TreeNode> nextLevel = new LinkedList<TreeNode>();
currLevel.add(root);
while(currLevel.size() > 0) {
ArrayList<Integer> thisLevel = new ArrayList<Integer>();
while(currLevel.size() > 0) {
TreeNode curr = currLevel.poll();
thisLevel.add(curr.val);
if(curr.left != null) nextLevel.add(curr.left);
if(curr.right != null) nextLevel.add(curr.right);
}
res.add(thisLevel);
currLevel = nextLevel;
nextLevel = new LinkedList<TreeNode>();
}
return res;
}
}