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Coding workflows · Undirected bridge edges
03
A concrete starting point
Find bridges in a simple undirected graph with at most 32 vertices. Test disconnected components and cycles, rejecting duplicate edges, self-loops and invalid endpoints without changing the input.
Define the change
Describe the input, expected output and boundaries that must stay intact.
Inspect the work
Review the proposed edits and any commands before relying on their result.
Check the outcome
Compare actual behavior with the expected result. If a check fails, investigate it before applying more changes.
Undirected bridge edges
A concrete starting point
def bridge_edges(n, edges):
if type(n) is not int or not 0 <= n <= 32:
raise ValueError("vertex count")
if type(edges) is not list or len(edges) > 496:
raise ValueError("edge count")
graph = [set() for _ in range(n)]
for edge in edges:
if type(edge) is not tuple or len(edge) != 2 or any(
type(x) is not int or not 0 <= x < n for x in edge):
raise ValueError("edge endpoints")
a, b = edge
if a == b or b in graph[a]:
raise ValueError("simple undirected edges")
graph[a].add(b); graph[b].add(a)
timer, found = 0, []
entered, low = [-1] * n, [0] * n
def visit(v, parent):
nonlocal timer
entered[v] = low[v] = timer; timer += 1
for u in sorted(graph[v]):
if u == parent:
continue
if entered[u] < 0:
visit(u, v); low[v] = min(low[v], low[u])
if low[u] > entered[v]:
found.append(tuple(sorted((v, u))))
else:
low[v] = min(low[v], entered[u])
for v in range(n):
if entered[v] < 0:
visit(v, -1)
return sorted(found)The example is a starting point for a real project, not a claim that generated code is already tested. Adjust paths, dependencies and expected behavior to match your application.