说白了这道题的难点就是如何求每一层的结点值之和,肯定需要遍历整个二叉树,用什么样的遍历方式呢,当然是用层序最方便啦,LeetCode 中有考察层序遍历的题,Binary Tree Level Order Traversal和 Binary Tree Level Order Traversal II,做过这两道的话,这道题也就没啥难度了。这里还是用 queue 来辅助遍历,先将根...
Given therootof a binary tree, the level of its root is1, the level of its children is2, and so on. Return the smallest levelXsuch that the sum of all the values of nodes at levelXis maximal. Example 1: Input:[1,7,0,7,-8,null,null] Output:2 Explanation: Level 1 sum = 1. ...
Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. For example: Given the below binary tree andsum = 22, 5 / \ 4 8 / / \ 11 13 4 / \ \ 7 2 1 1. 2. 3. 4. 5. 6. ...
# Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self.right = right class Solution: def rangeSumBST(self, root: Optional[TreeNode], low: int, high: int) -> int: # 如果 roo...
Leetcode Binary Tree Maximum Path Sum Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example: Given the below binary tree, 1 / \ 2 3 1. 2. 3. Return6. 对于每个结点,我们需要比较三个值。
Can you solve this real interview question? Binary Search Tree to Greater Sum Tree - Given the root of a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus the sum of all key
题目链接:Path Sum II | LeetCode OJ Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example: Given the below binary tree and sum = 22, 5 /\ 48 //\ 11134 /\/\ ...
【LeetCode】Sum Root to Leaf Numbers 题目Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 which represents the number 123. Find the total sum of all root-to-leaf numbers. For example,...
【Binary Indexed Tree/树状数组】307. Range Sum Query - Mutable 3915 -- 9:29 App LeetCode 920. Number of Music Playlists 186 -- 10:33 App [English] LeetCode 233. Number of Digit One 399 -- 12:49 App LeetCode 1074. Number of Submatrices That Sum to Target 1329 8 10:24 App ...
http://www.programcreek.com/2013/02/leetcode-binary-tree-maximum-path-sum-java/ 另外,这道题目的BST条件,似乎没什么用。因为如果全是负数,BST也没帮助了。 ** 总结: pre-order -> top-down post-order -> bottom-up in-order -> ? level-order -> bfs ...