100 lines
2.3 KiB
Java
100 lines
2.3 KiB
Java
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//给定一个二叉树的 根节点 root，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。
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//
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//
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//
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// 示例 1:
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//
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//
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//
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//输入: [1,2,3,null,5,null,4]
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//输出: [1,3,4]
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//
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//
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// 示例 2:
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//
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//
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//输入: [1,null,3]
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//输出: [1,3]
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//
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//
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// 示例 3:
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//
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//
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//输入: []
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//输出: []
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//
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//
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//
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//
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// 提示:
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//
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//
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// 二叉树的节点个数的范围是 [0,100]
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// -100 <= Node.val <= 100
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//
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// Related Topics 树 深度优先搜索 广度优先搜索 二叉树
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// 👍 502 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.TreeNode;
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import java.util.ArrayList;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.Queue;
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//199:二叉树的右视图
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public class BinaryTreeRightSideView {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new BinaryTreeRightSideView().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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/**
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* Definition for a binary tree node.
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* public class TreeNode {
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* int val;
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* TreeNode left;
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* TreeNode right;
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* TreeNode() {}
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* TreeNode(int val) { this.val = val; }
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* TreeNode(int val, TreeNode left, TreeNode right) {
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* this.val = val;
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* this.left = left;
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* this.right = right;
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* }
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* }
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*/
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class Solution {
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public List<Integer> rightSideView(TreeNode root) {
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List<Integer> list = new ArrayList<>();
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if (root == null) {
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return list;
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}
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Queue<TreeNode> queue = new LinkedList<>();
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queue.offer(root);
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while (!queue.isEmpty()) {
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int size = queue.size();
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for (int i = 1; i <= size; i++) {
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TreeNode node = queue.poll();
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if (node.left != null) {
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queue.offer(node.left);
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}
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if (node.right != null) {
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queue.offer(node.right);
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}
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if (i == size) {
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list.add(node.val);
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}
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}
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}
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return list;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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