# 二叉树的右视图

<p>给定一个二叉树的 <strong>根节点</strong> <code>root</code>，想象自己站在它的右侧，按照从顶部到底部的顺序，返回从右侧所能看到的节点值。</p>

<p> </p>

<p><strong>示例 1:</strong></p>

<p><img src="https://assets.leetcode.com/uploads/2021/02/14/tree.jpg" style="width: 270px; " /></p>

<pre>
<strong>输入:</strong> [1,2,3,null,5,null,4]
<strong>输出:</strong> [1,3,4]
</pre>

<p><strong>示例 2:</strong></p>

<pre>
<strong>输入:</strong> [1,null,3]
<strong>输出:</strong> [1,3]
</pre>

<p><strong>示例 3:</strong></p>

<pre>
<strong>输入:</strong> []
<strong>输出:</strong> []
</pre>

<p> </p>

<p><strong>提示:</strong></p>

<ul>
	<li>二叉树的节点个数的范围是 <code>[0,100]</code></li>
	<li><meta charset="UTF-8" /><code>-100 <= Node.val <= 100</code> </li>
</ul>


## template

```java
public class TreeNode {
	int val;
	TreeNode left;
	TreeNode right;

	TreeNode(int x) {
		val = x;
	}
}

class Solution {
	public List<Integer> rightSideView(TreeNode root) {
		List<Integer> list = new ArrayList<Integer>();
		if (root == null)
			return list;

		list.add(root.val);
		List<Integer> list1 = rightSideView(root.right);
		List<Integer> list2 = rightSideView(root.left);

		list.addAll(list1);

		if (list1.size() < list2.size()) {
			for (int i = list1.size(); i < list2.size(); i++) {
				list.add(list2.get(i));
			}
		}

		return list;
	}
}

```

## 答案

```java

```

## 选项

### A

```java

```

### B

```java

```

### C

```java

```