513. 找树左下角的值

 1 import java.util.LinkedList;
 2 import java.util.Queue;
 3 
 4 public class FindBottomLeftValue {
 5     static class TreeNode {
 6         int val;
 7         TreeNode left;
 8         TreeNode right;
 9         TreeNode(int x) {
10             val = x;
11         }
12     }
13     public int findBottomLeftValue(TreeNode root) {
14         Queue<TreeNode> queue = new LinkedList<>();
15         TreeNode temp = root;
16         queue.add(root);
17         while(!queue.isEmpty()) {
18             temp = queue.remove();
19             //先将右子节点添加，从右往左，则可以最后访问最左侧节点
20             if(temp.right != null) {
21                 queue.add(temp.right);
22             }
23             if(temp.left != null) {
24                 queue.add(temp.left);
25             }
26         }
27         return temp.val;
28     }    
29 }