Practice Cousins in Binary Tree II

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#2641

LeetCode Problem

Cousins in Binary Tree II

Hash Table Tree Depth-First Search Breadth-First Search Binary Tree

Problem Statement

Given the root of a binary tree, replace the value of each node in the tree with the sum of all its cousins' values. Two nodes of a binary tree are cousins if they have the same depth with different parents. Return the root of the modified tree. Note that the depth of a node is the number of edges in the path from the root node to it.

Source: Cousins in Binary Tree II on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input

root = [5,4,9,1,10,null,7]

Output

[0,0,0,7,7,null,11]

# Example 2

Input

root = [3,1,2]

Output

[0,0,0]

Constraints

The number of nodes in the tree is in the range [1, 10^5].

1 <= Node.val <= 10^4

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