Discrete StructureTU Board 2023
Using Dijkstra's Algorithm, find the shortest distance from source vertex 'A' to 'D' and 'E' in the following graph. [figure in the original paper]
3Answer
PPadhai · Based on the official syllabus and past papers
Updated Given weighted graph (undirected, weights shown on edges)
Step-by-Step Application of Dijkstra’s Algorithm (Source = A)
Initialization
- Set distance to source A as 0, all others as ∞.
- Set all vertices as unvisited.
- Initialize priority queue Q with (A,0).
| Vertex |
Distance |
Visited |
| A |
0 |
No |
| B |
∞ |
No |
| C |
∞ |
No |
| D |
∞ |
No |
| E |
∞ |
No |
- Update neighbors of A:
- B: min(∞,0+4)=4
- C: min(∞,0+2)=2
- Mark A as visited.
| Vertex |
Distance |
Visited |
| B |
4 |
No |
| C |
2 |
No |
| D |
∞ |
No |
| E |
∞ |
No |
- Update neighbors of C:
- B: min(4,2+1)=3 (no change, since 3 > 4)
- D: min(∞,2+8)=10
- E: min(∞,2+10)=12
- Mark C as visited.
| Vertex |
Distance |
Visited |
| B |
3 |
No |
| D |
10 |
No |
| E |
12 |
No |
- Update neighbors of B:
- Mark B as visited.
| Vertex |
Distance |
Visited |
| D |
8 |
No |
| E |
12 |
No |
- Update neighbor of D:
- Mark D as visited.
| Vertex |
Distance |
Visited |
| E |
10 |
No |
- No updates needed.
- Mark E as visited.
Final Shortest Distances
- Distance from A to D: 8 (Path: A→C→D)
- Distance from A to E: 10 (Path: A→C→D→E)
Shortest paths highlighted (A→D: 8, A→E: 10)
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