Employee Referral Program

We are running a referral campaign. Every time an existing user invites a brand-new user to the platform, the inviter becomes responsible for that new user and for every user the new user later invites, and so on down the chain. Your task is to build a referral leaderboard from the invitation records. You are given two arrays that describe the invitations in chronological order: referrers – the list of users who sent an invitation referrals – the corresponding users who…