Chen
November 17, 2022
92

# Dijkstra’s Algorithm

## Chen

November 17, 2022

## Transcript

1. Dijkstra’s Algorithm
Do Dijkstra’s on this graph, starting from A.
Best distance to A: 0
All other nodes: 1 (so far, unreachable)
52 / 71

2. Dijkstra’s Algorithm
A is done. Choose shortest total distance (B at distance 3)
From B, ﬁnd a better path to C (3+3=6)
Path to A is worse (3+3, worse than 0)
53 / 71

3. Dijkstra’s Algorithm
B is done. Choose shortest total distance (F at distance 4)
Better path to E (4+5=9)
Worse paths to A (4+4 vs 0) and D (4+2=6 vs 5)
54 / 71

4. Dijkstra’s Algorithm
F is done. Choose shortest total distance (D at distance 5)
Better path for E (5+3 = 8 vs 9)
Worse paths for other nodes
55 / 71

5. Dijkstra’s Algorithm
D is done. Choose shortest total distance (C at distance 6)
Better path to E (6+1 = 7 vs 8)
Worse paths to B and D
56 / 71

6. Dijkstra’s Algorithm
C is done. Choose shortest total distance (E at distance 7)
Worse paths everywhere
57 / 71

7. Dijkstra’s Algorithm
All nodes are done.
Note we could have recorded paths in table
Also could stop early if we only wanted a single destination.
58 / 71