Detect Graph Cycle | Dataford Interview Questions

Write a piece of code that detects a cycle in a graph.

Treat the graph as directed and represented by an adjacency-list dictionary. Return True if any directed cycle exists, including a self-loop, otherwise return False. The function must inspect disconnected components, and a neighbor absent from the dictionary should be treated as a node with no outgoing edges.

Use def has_cycle(graph):, where graph is a JSON object whose keys identify nodes and whose values are lists of neighboring node identifiers. Return a boolean.

Constraints

0 <= number of listed nodes <= 10^4
Each node identifier is representable as a JSON string or integer
The total number of adjacency entries is at most 5 * 10^4
The graph is directed
A neighbor absent from the dictionary has no outgoing edges

Function Signature

def has_cycle(graph):

Your question is Detect Graph Cycle. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Write a piece of code that detects a cycle in a graph.

Use def has_cycle(graph):, where graph is a JSON object whose keys identify nodes and whose values are lists of neighboring node identifiers. Return a boolean.

Constraints

0 <= number of listed nodes <= 10^4
Each node identifier is representable as a JSON string or integer
The total number of adjacency entries is at most 5 * 10^4
The graph is directed
A neighbor absent from the dictionary has no outgoing edges

Function Signature

def has_cycle(graph):

Your question is Detect Graph Cycle. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.