How should I practice Distance Between Two Tree Nodes?

Start by reading the full statement, solve the visible examples, then compare the pattern against related Amazon phone screen and onsite interview problems in FastPrep.

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Distance Between Two Tree Nodes

Amazon● MediumFULLTIMEPHONE SCREENONSITE INTERVIEW

Problem statement

You are given a rooted tree whose nodes are numbered from 1 through treeNodes. The arrays treeFrom and treeTo describe the undirected edges of the tree, and root identifies its root.

Given two node IDs source and target, return the number of edges on the unique path between them.

The serialized edge list supplies the tree structure without parent pointers.

Function

distanceBetweenNodes(treeNodes: int, treeFrom: int[], treeTo: int[], root: int, source: int, target: int) → int

Examples

Example 1

treeNodes = 7treeFrom = [1,1,2,2,3,3]treeTo = [2,3,4,5,6,7]root = 1source = 4target = 7return = 4

The unique path is 4 -> 2 -> 1 -> 3 -> 7, which contains 4 edges.

Example 2

treeNodes = 5treeFrom = [1,1,3,3]treeTo = [2,3,4,5]root = 1source = 3target = 5return = 1

Node 5 is adjacent to node 3, so their distance is 1.