LeetCode 515. 在每个树行中找最大值(Find Largest Value in Each Tree Row)

客官°小女子只卖身不卖艺 2021-11-22 06:02 257阅读 0赞

**515. 在每个树行中找最大值**  
**515. Find Largest Value in Each Tree Row**

**题目描述**  
You need to find the largest value in each row of a binary tree.

您需要在二叉树的每一行中找到最大的值。

LeetCode515. Find Largest Value in Each Tree Row

**Example:**

**Input:**

1
             / \
            3   2
           / \   \  
          5   3   9

**Output:** \[1, 3, 9\]

**Java 实现**  
**TreeNode Class**

class TreeNode { int val; TreeNode left; TreeNode right; TreeNode(int x) { val = x; } }

import java.util.LinkedList; import java.util.List; class Solution { public List<Integer> largestValues(TreeNode root) { List<Integer> res = new LinkedList<>(); helper(root, res, 0); return res; } public void helper(TreeNode root, List<Integer> res, int depth) { if (root == null) { return; } if (depth == res.size()) { res.add(root.val); } else { res.set(depth, Math.max(res.get(depth), root.val)); } helper(root.left, res, depth + 1); helper(root.right, res, depth + 1); } }

**参考资料**

*  [https://leetcode.com/problems/find-largest-value-in-each-tree-row/][https_leetcode.com_problems_find-largest-value-in-each-tree-row]
 *  [https://leetcode-cn.com/problems/find-largest-value-in-each-tree-row/][https_leetcode-cn.com_problems_find-largest-value-in-each-tree-row]
 *  [https://leetcode.com/problems/find-largest-value-in-each-tree-row/discuss/98971/9ms-JAVA-DFS-solution][https_leetcode.com_problems_find-largest-value-in-each-tree-row_discuss_98971_9ms-JAVA-DFS-solution]

转载于:https://www.cnblogs.com/hglibin/p/10891088.html

[https_leetcode.com_problems_find-largest-value-in-each-tree-row]: https://leetcode.com/problems/find-largest-value-in-each-tree-row/
[https_leetcode-cn.com_problems_find-largest-value-in-each-tree-row]: https://leetcode-cn.com/problems/find-largest-value-in-each-tree-row/
[https_leetcode.com_problems_find-largest-value-in-each-tree-row_discuss_98971_9ms-JAVA-DFS-solution]: https://leetcode.com/problems/find-largest-value-in-each-tree-row/discuss/98971/9ms-JAVA-DFS-solution