Graph traversal: count connected components with adjacency traversal

Graph traversal: Given n nodes numbered 0 through n-1 and undirected edges, return the number of connected components, including isolated nodes.

Input: A JSON object { "n": number, "edges": [number, number][] }.

Output: A JSON integer component count.

Constraints:

0 <= n <= 100000
Every edge endpoint is in 0..n-1
Self-edges and repeated edges do not create extra components

Read one JSON value from stdin and print exactly one JSON-serialized answer to stdout with no extra text.

Difficulty: MEDIUM. Variant: 14. Expect follow-up questions about complexity, edge cases, and alternative approaches.

Practice context

This coding (algo) exercise trains prompt interpretation, explicit assumptions, a concrete response, and a concise explanation of the decisions made. It is marked medium difficulty.

The signed-in workspace provides the tools required by the round, such as recording,

What this task practices

This coding (algo) exercise trains the same sequence expected in an interview: understand the prompt, make assumptions explicit, produce a concrete answer, and explain the decisions behind it. The task is marked medium difficulty. The private workspace adds the tools required by this round, such as recording, code execution, diagrams, evidence panels, or structured notes. It also preserves the attempt so later feedback can be compared with previous work. Evaluation is based on task-specific criteria and the candidate seniority selected in the preparation path. Public pages never expose the reference solution, hidden tests, evaluator instructions, or another candidate’s work.