How do I implement the Bellman-Ford algorithm in Python?

How do I implement the Bellman-Ford algorithm in Python?

To implement the Bellman-Ford algorithm in Python, you need to define a function that takes the number of vertices, edges, and the source vertex.

Can you show me a sample code for that?

Sure! Here's a simple implementation:

class Edge:
    def __init__(self, u, v, weight):
        self.u = u
        self.v = v
        self.weight = weight

def bellman_ford(vertices, edges, source):
    distance = [float('inf')] * vertices
    distance[source] = 0

    for _ in range(vertices - 1):
        for edge in edges:
            if distance[edge.u] + edge.weight < distance[edge.v]:
                distance[edge.v] = distance[edge.u] + edge.weight

    return distance

What if there are negative weight cycles?

If there are negative weight cycles, the Bellman-Ford algorithm can detect them. After the main loop, you can add another loop to check for updates. If any distance can still be minimized, a negative cycle exists.