How should I practice Minimum Friend API Calls?

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

Is Minimum Friend API Calls associated with Mercor?

FastPrep tags this as a Mercor onsite interview coding practice problem when the problem catalog has that company and stage context.

Minimum Friend API Calls

Mercor● MediumFULLTIMEONSITE INTERVIEW

Learn

Problem statement

A friendship service exposes one operation: querying a user returns that user's direct friends. Each query counts as one API call.

You are given the complete undirected friendship pairs for an offline practice adapter, plus source and target. Return the minimum number of friend-list API calls along any chain from source to target. Return 0 when they are the same user and -1 when no chain exists.

Function

minimumFriendApiCalls(friendships: String[][], source: String, target: String) → int

Examples

Example 1

friendships = [["a","b"],["b","c"],["c","d"]]source = "a"target = "d"return = 3

The shortest chain has three friendship edges.

Example 2

friendships = [["alice","bob"]]source = "alice"target = "bob"return = 1

One query reaches the direct friend.

Example 3

friendships = [["a","b"],["c","d"]]source = "a"target = "d"return = -1

The users are in different connected components.

Constraints

0 <= friendships.length <= 100000
Every pair contains two distinct nonempty user IDs of at most 40 characters.
source and target are nonempty user IDs.
Duplicate friendship pairs do not change the result.