Assess students' ability to apply Dijkstra's algorithm to nonnegative weighted graphs by tracing and implementing the algorithm with different priority queue structures (e.g., binary heap, Fibonacci heap, unsorted array). Tasks will include: step-by-step execution on small example graphs (showing distance updates, extract-min, and decrease-key operations), writing or describing pseudocode for each PQ-backed variant, and analyzing time/space complexity and practical trade-offs (sparse vs. dense graphs, constant factors, implementation complexity). Expect correctness checks, complexity derivations, and a short comparative evaluation of which PQ is most suitable under given constraints.