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Practice Validate Binary Tree Nodes

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

Medium#1361
LeetCode Problem

Validate Binary Tree Nodes

TreeDepth-First SearchBreadth-First SearchUnion FindGraphBinary Tree

Problem Statement

You have n binary tree nodes numbered from 0 to n - 1 where node i has two children leftChild[i] and rightChild[i], return true if and only if all the given nodes form exactly one valid binary tree. If node i has no left child then leftChild[i] will equal -1, similarly for the right child. Note that the nodes have no values and that we only use the node numbers in this problem.

Source: Validate Binary Tree Nodes on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input
n = 4, leftChild = [1,-1,3,-1], rightChild = [2,-1,-1,-1]
Output
true

# Example 2

Input
n = 4, leftChild = [1,-1,3,-1], rightChild = [2,3,-1,-1]
Output
false

# Example 3

Input
n = 2, leftChild = [1,0], rightChild = [-1,-1]
Output
false

Constraints

n == leftChild.length == rightChild.length
1 <= n <= 10^4
-1 <= leftChild[i], rightChild[i] <= n - 1

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100 Same Tree Easy101 Symmetric Tree Easy104 Maximum Depth of Binary Tree Easy111 Minimum Depth of Binary Tree Easy112 Path Sum Easy
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