Graph Algorithms Tutorial

cds.graph implements traversal, shortest paths, MST, topo sort, and cycle detection on a small Graph class.

1. Build a Graph

from cds.graph import Graph

g = Graph(directed=False)
for u, v, w in [("A","B",4), ("A","C",2), ("B","C",1), ("B","D",5), ("C","D",8)]:
    g.add_edge(u, v, weight=w)

2. Traversal

from cds.graph import bfs, dfs

print(bfs(g, "A"))
print(dfs(g, "A"))

3. Shortest Paths & MST

from cds.graph import dijkstra, kruskal_mst

print(dijkstra(g, "A"))   # {node: distance}
print(kruskal_mst(g))     # list of (u, v, weight)

4. Topological Sort & Cycles

from cds.graph import Graph, topological_sort, has_cycle

dag = Graph(directed=True)
dag.add_edge("a", "b")
dag.add_edge("b", "c")
print(topological_sort(dag))  # valid ordering
print(has_cycle(dag))         # False

Run the full demo with python examples/graph_demo.py.