Practice Question-2 (BFS)
Duration: 2 min
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AI Summary
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This educational video segment addresses a GATE-2017 multiple-choice question on Breadth First Search (BFS) traversal. The problem requires identifying a valid node visiting order for a specific graph using a queue data structure. Four options are presented: MNOPQR, NQMPOR, QMNROP, and POQNMR. The instructor systematically evaluates each sequence against the graph's connectivity rules inherent to BFS, which mandates layer-by-layer exploration. By analyzing adjacency and queue behavior, the instructor eliminates incorrect options (a, b, c) based on violations of traversal logic. The session concludes by validating option (d), POQNMR, as the correct sequence that satisfies the BFS constraints for the given graph structure.
Chapters
0:00 – 2:00 00:00-02:00
The video introduces a GATE-2017 problem asking for a possible BFS visiting order using a queue. Visible text displays the question: 'Which one of the following is a possible order of visiting the nodes in the graph above?' alongside options (a) MNOPQR, (b) NQMPOR, (c) QMNROP, and (d) POQNMR. The instructor begins analyzing the graph structure involving nodes M, N, O, P, Q, R. Evidence includes on-screen text highlighting 'Breath First Search (BFS) has been implemented using queue data structure' and the specific graph nodes listed. The instructor focuses on checking adjacency list orders to verify if sequences respect BFS layer-by-layer traversal properties.
2:00 – 2:17 02:00-02:17
In the final segment, the instructor completes the evaluation of the BFS options. The visible evidence shows the instructor crossing out incorrect answers (a, b, and c) while validating option (d). The text on screen confirms the graph nodes M, N, Q, R, O, P. The instructor selects option (d) POQNMR as the correct answer because it aligns with queue-based traversal logic. This conclusion is drawn from eliminating impossible node sequences that violate the connectivity rules of the provided graph.
The lecture segment effectively demonstrates the application of Breadth First Search (BFS) traversal logic through a specific GATE-2017 examination problem. The core concept tested is the strict adherence to queue-based, layer-by-layer node visitation in graph theory. The instructor's method involves verifying each multiple-choice option against the graph's adjacency constraints, ensuring that neighbors are visited before their children. By systematically eliminating options (a), (b), and (c) due to logical inconsistencies with the graph structure, the instructor isolates option (d), POQNMR, as the only valid sequence. This approach reinforces the importance of understanding queue mechanics in BFS algorithms for solving traversal problems.