【ツリー】ツリーの右ビュー
1481 ワード
一、テーマ
力扣原题:https://leetcode-cn.com/problems/binary-tree-right-side-view/
二、BFS検索 /**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List rightSideView(TreeNode root) {
if (null == root) {
return new ArrayList<>();
}
List rightSideView = new ArrayList<>();
List records = new ArrayList<>();
records.add(root);
while (!records.isEmpty()) {
//
List childs = new ArrayList<>();
for (TreeNode node : records) {
if (null != node.left) {
childs.add(node.left);
}
if (null != node.right) {
childs.add(node.right);
}
}
//
rightSideView.add(records.get(records.size() - 1).val);
// records
records = childs;
}
return rightSideView;
}
}
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
class Solution {
public List rightSideView(TreeNode root) {
if (null == root) {
return new ArrayList<>();
}
List rightSideView = new ArrayList<>();
List records = new ArrayList<>();
records.add(root);
while (!records.isEmpty()) {
//
List childs = new ArrayList<>();
for (TreeNode node : records) {
if (null != node.left) {
childs.add(node.left);
}
if (null != node.right) {
childs.add(node.right);
}
}
//
rightSideView.add(records.get(records.size() - 1).val);
// records
records = childs;
}
return rightSideView;
}
}