LeetCode: Find Bottom Left Tree Value

 1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 public class Solution {
11     public int findBottomLeftValue(TreeNode root) {
12         Deque<TreeNode> row = new LinkedList<TreeNode>();
13         row.add(root);
14         int ans = 0;
15         while (row.isEmpty() != true) {
16             int size = row.size();
17             for (int i = 0; i < size; i++) {
18                 TreeNode node = row.poll();
19                 if (i == 0) ans = node.val;
20                 if (node.left != null) row.add(node.left);
21                 if (node.right != null) row.add(node.right);
22             }
23         }
24         return ans;
25     }
26 }