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Dijkstra's shortest path algorithm

Aya Bouchiha
Full stack web developer
・2 min read

Hello, this is #day_29, I'm going to talk about Dijkstra's shortest path algorithm

Definition of Dijkstra's shortest path algorithm

dijkstra's shortest path is an algorithm created by Dr. Edsger Dijkstra for calculating the shortest path between vertices in a weighted graph (types of graph)

Example of a weighted graph

weighted graph aya bouchiha

Dijkstra's shortest path applications

  • Road networks
  • Electricity lines
  • Google maps
  • Social networking apps
  • Flighting agenda
  • Ip routing more details

Dijkstra's shortest path implementation in python

If you are not familiar with Python check this series by @aatmaj


def dijkstraShortestPathAlgo(nodes, edges, source_indedx = 0):
    """
        code from 
        => [https://www.youtube.com/watch?v=VnTlW572Sc4]
    """
    path_lengths = {v:float('inf') for v in nodes}
    path_lengths[source_index] = 0
    adjacent_nodes = {v:{} for v in nodes}
    for (u, v), w_uv in edges.items():
        adjacent_nodes[u][v] = w_uv
        adjacent_nodes[v][u] = w_uv
    temporary_nodes = [v for v in nodes]
    while len(temporary_nodes) > 0:
        upper_bounds = {v: path_lengths[v] for v in temporary_nodes}
        u = min(upper_bounds, key=upper_bounds.get)
        temporary_nodes.remove(u)
        for v, w_uv in adjacent_nodes[u].items():
            path_lengths[v] = min(path_lengths[v], path_lengths[u] + w_uv)
    return path_lengths
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more details...

References & useful resources

Happy coding!!

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