How should I practice Lowest Common Ancestor in an N-ary Tree?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Bloomberg LP phone screen problems in FastPrep.

Is Lowest Common Ancestor in an N-ary Tree associated with Bloomberg LP?

FastPrep tags this as a Bloomberg LP phone screen coding practice problem when the problem catalog has that company and stage context.

Lowest Common Ancestor in an N-ary Tree

Bloomberg LP● MediumFULLTIMEPHONE SCREEN

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Problem statement

A rooted N-ary tree has nodes labeled from 0 through n - 1. It is encoded by parent, where parent[root] = -1 and every other value gives the node's direct parent.

Given two valid node labels p and q, return their lowest common ancestor: the deepest node that is an ancestor of both. A node is an ancestor of itself.

Function

lowestCommonAncestor(parent: int[], p: int, q: int) → int

Examples

Example 1

parent = [-1,0,0,1,1,2,2,3]p = 7q = 4return = 1

Node 1 is the deepest shared ancestor of nodes 7 and 4.

Example 2

parent = [-1,0,0,1,1,2,2]p = 5q = 6return = 2

Both queried nodes are direct children of node 2.

Constraints

1 <= parent.length <= 200000.
Exactly one entry is -1; every other entry is a valid node label.
The parent relationships form one connected acyclic rooted tree.
0 <= p, q < parent.length.