Add solution for Challenge 4 by Raycas96

[Raycas96]

Challenge 4 Solution

Submitted by: @Raycas96
Challenge: Challenge 4

Description

This PR contains my solution for Challenge 4.

Changes

• Added solution file to challenge-4/submissions/Raycas96/solution-template.go

Testing

• Solution passes all test cases
• Code follows Go best practices

Thank you for reviewing my submission! 🚀

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No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 9162ae4d-7b2f-4371-bb39-7eec89e9e312

📥 Commits

Reviewing files that changed from the base of the PR and between 6a002af and 6dff3a6.

📒 Files selected for processing (1)

• challenge-4/submissions/Raycas96/solution-template.go

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Walkthrough

Added concurrent BFS query processing using worker pools, channels, and goroutines to handle multiple breadth-first search operations in parallel over an adjacency-list graph, returning a map of start nodes to their traversal orders.

Changes

Cohort / File(s)	Summary
Concurrent BFS Implementation challenge-4/submissions/Raycas96/solution-template.go	Added BFSResult struct, standardBFS() function for single-source BFS with visited set and FIFO queue, and ConcurrentBFSQueries() function implementing worker pool pattern with buffered channels for distributing and collecting query results across multiple goroutines.

Sequence Diagram(s)

sequenceDiagram
    participant Main as Main Thread
    participant JobsCh as jobs Channel
    participant Worker as Worker Goroutines
    participant Graph as standardBFS
    participant ResultsCh as results Channel

    Main->>JobsCh: Enqueue all query start nodes
    Main->>JobsCh: Close channel
    
    par Concurrent Workers
        Worker->>JobsCh: Receive start node
        Worker->>Graph: Execute BFS traversal
        Graph->>Worker: Return BFS order
        Worker->>ResultsCh: Send BFSResult
    and
        Worker->>JobsCh: Receive start node
        Worker->>Graph: Execute BFS traversal
        Graph->>Worker: Return BFS order
        Worker->>ResultsCh: Send BFSResult
    end
    
    Main->>ResultsCh: Collect all results (len(queries))
    Main->>Main: Build map[start node → BFS order]
    Main->>Main: Return final map

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Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Possibly related PRs

• #1178: Implements the same ConcurrentBFSQueries function with per-query BFS worker pool processing.
• #1122: Adds identical concurrent BFS worker pool implementation with channel-based job distribution and result collection.
• #606: Implements the same concurrent BFS query functionality using worker pools and channels for multiple start nodes.

Poem

🐰 A worker pool hops through the graph so wide,
With channels flowing like a bunny's stride,
Each query bounded by goroutines so fleet,
BFS orders—concurrent and neat! 🌳

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies that this PR adds a solution for Challenge 4 by a specific contributor (Raycas96), which directly matches the changeset content.
Description check	✅ Passed	The description is directly related to the changeset, explaining that it contains a Challenge 4 solution submission with details about the file added and testing performed.

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[github-actions]

🎉 Auto-merged!

This PR was automatically merged after 2 days with all checks passing.

Thank you for your contribution, @Raycas96!