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+19 votes
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Suppose we run Dijkstra’s single source shortest-path algorithm on the following edge-weighted directed graph with vertex $P$ as the source.

     

In what order do the nodes get included into the set of vertices for which the shortest path distances are finalized?

  1. $P,Q,R,S,T,U$
  2. $P,Q,R,U,S,T$
  3. $P,Q,R,U,T,S$
  4. $P,Q,T,R,U,S$
asked in Algorithms by Veteran (59.7k points)
edited by | 2k views

2 Answers

+18 votes
Best answer

Answer is (B). In Dijkstra's algorithm at each point we choose the smallest weight edge which starts from any one of the vertices in the shortest path found so far and add it to the shortest path.

answered by Junior (767 points)
edited by
+1
Ans (C) is also possible in this case.. so, what is the answer ? confused about it.
+1
(c )can not be an answer  according to dijikstras algorithm

reaching node R  , edge to S and U from R is relaxed which gives node S value - 4 and node U value as 3 therefore we wil choose U now and after that  S and at the and T
0
Why we prefer S-T(cost to reach from P is 8) over P-T(Cost is 7)?

Is in Dijkstra from a vertex only one outgoing edge(of minimum weight) is allowed?
+6 votes

Answer will be "B" 

answered by Loyal (8.2k points)
Answer:

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