LeetCode 솔루션

[12/11] 124. Binary Tree Maximum Path Sum

학부유학생 쪽지보내기 메일보내기 자기소개 아이디로 검색 전체게시물 작성
작성일 2022.12.12 14:37

6,139 조회
1 댓글
0 추천
0 비추천
목록 게시글 쓰기

A path in a binary tree is a sequence of nodes where each pair of adjacent nodes in the sequence has an edge connecting them. A node can only appear in the sequence at most once. Note that the path does not need to pass through the root.

The path sum of a path is the sum of the node's values in the path.

Given the root of a binary tree, return the maximum path sum of any non-empty path.

Example 1:

Input: root = [1,2,3]
Output: 6
Explanation: The optimal path is 2 -> 1 -> 3 with a path sum of 2 + 1 + 3 = 6.

Example 2:

Input: root = [-10,9,20,null,null,15,7]
Output: 42
Explanation: The optimal path is 15 -> 20 -> 7 with a path sum of 15 + 20 + 7 = 42.

Constraints:

The number of nodes in the tree is in the range [1, 3 * 104].
-1000 <= Node.val <= 1000

Accepted

<div class="text-label-1 dark:text-dark-label-1 text-sm font-medium" style="border: 0px solid; box-sizing: border-box; --tw-border-spacing-x:0; --tw-border-spacing-y:0; --tw-translate-x:0; --tw-translate-y:0; --tw-rotate:0; --tw-skew-x:0; --tw-skew-y:0; --tw-scale-x:1; --tw-scale-y:1; --tw-pan-x: ; --tw-pan-y: ; --tw-pinch-zoom: ; --tw-scroll-snap-strictness:proximity; --tw-ordinal: ; --tw-slashed-zero: ; --tw-numeric-figure: ; --tw-numeric-spacing: ; --tw-numeric-fraction: ; --tw-ring-inset: ; --tw-ring-offset-width:0px; --tw-ring-offset-color:#fff; --tw-ring-color:rgba(59,130,246,0.5); --tw-ring-offset-shadow:0 0 #0000; --tw-ring-shadow:0 0 #0000; --tw-shadow:0 0 #0000; --tw-shadow-colored:0 0 #0000; --tw-blur: ; --tw-brightness: ; --tw-contrast: ; --tw-grayscale: ; --tw-hue-rotate: ; --tw-invert: ; --tw-saturate: ; --tw-sepia: ; --tw-drop-shadow: ; --tw-backdrop-blur: ; --tw-backdrop-brightness: ; --tw-backdrop-contrast: ; --tw-backdrop-grayscale: ; -

#DoorDash, #Microsoft, #Amazon, #Facebook, #Bloomberg, #Adobe, #Apple, #Samsung, #TikTok, #Akuna Capital

링크

https://leetcode.com/problems/binary-tree-maximum-path-sum/ 2757 회 연결

익명
작성일 2022.12.12 14:37

# 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 maxPathSum(self, root: Optional[TreeNode]) -> int:
        max_path = float('-inf')

        def dfs(node):
            if not node: return 0
            nonlocal max_path

            left = dfs(node.left)
            right = dfs(node.right)

            max_path = max(max_path, node.val+right + left, node.val+left, node.val+right, node.val)

            return max(node.val + right, node.val + left, node.val)
        
        dfs(root)
        return max_path