Java for LeetCode 199 Binary Tree Right Side View

標籤：

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.

For example:
Given the following binary tree,

   1            <--- /   2     3         <--- \       5     4       <---

You should return [1, 3, 4].

解題思路：

DFS，帶個height即可，JAVA實現如下：

public List<Integer> rightSideView(TreeNode root) {List<Integer> list = new ArrayList<Integer>();if (root == null)return list;list.add(root.val);if (root.right != null)dfs(list, root.right, 1);if (root.left != null)dfs(list, root.left, 1);return list;}static void dfs(List<Integer> list, TreeNode root, int height) {if (height == list.size())list.add(root.val);if (root.right != null)dfs(list, root.right, height+1);if (root.left != null)dfs(list, root.left, height+1);}

 

Java for LeetCode 199 Binary Tree Right Side View