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AI Features

Feature #2: Copy Connections

Explore how to clone a Facebook user's friend connections on a graph structure by performing depth-first traversal and using hash tables to avoid cycles. Understand how to duplicate nodes accurately, manage unique user IDs, and analyze time and space complexity. This lesson helps you apply graph copying techniques to real-world interview problems involving social network data replication.

Description

After identifying every user’s friend circles, we need to duplicate this data to Instagram’s servers so it can be easily accessed and modified there as well. As the user’s name can be the same, so every user on Facebook gets assigned a unique id. Each Facebook user’s connections are represented and stored in a graph-like structure. We will first have to make an exact copy of this structure before storing it on Instagram’s servers.

Let’s say we want to duplicate the data for the following users:

For each user, we’ll be provided with a node and its information. This node will point to other nodes, and from that one node, we need to reach and make an exact clone of every other node. An edge between two nodes means that they are friends with each other. A bi-directional edge means that both users follow each ...