From 9c9442315ea02342fdbfb990d45511b6c25c8264 Mon Sep 17 00:00:00 2001
From: Vivek <103368320+Vivek09Chahal@users.noreply.github.com>
Date: Thu, 31 Oct 2024 09:10:16 +0530
Subject: [PATCH 1/2] Fix topological sort order
Fixes #12192
---
graphs/basic_graphs.py | 45 ++++++++++++++++++++++++++++++++----------
1 file changed, 35 insertions(+), 10 deletions(-)
diff --git a/graphs/basic_graphs.py b/graphs/basic_graphs.py
index 25c8045b3d2b..22b30ad8ff38 100644
--- a/graphs/basic_graphs.py
+++ b/graphs/basic_graphs.py
@@ -155,10 +155,30 @@ def dijk(g, s):
def topo(g, ind=None, q=None):
+ """
+ Perform topological sorting on a directed acyclic graph (DAG).
+
+ Args:
+ g (dict): Dictionary of edges representing the graph.
+ ind (list, optional): List of in-degrees of nodes. Defaults to None.
+ q (deque, optional): Queue for processing nodes. Defaults to None.
+
+ Returns:
+ list: List of nodes in topologically sorted order.
+
+ Note:
+ The function returns the list in the correct order from top to bottom.
+ The order is reversed before returning to ensure the correct topological sort.
+
+ Example:
+ >>> graph = {1: [2, 3], 2: [4], 3: [4], 4: []}
+ >>> topo(graph)
+ [1, 2, 3, 4]
+ """
if q is None:
q = [1]
if ind is None:
- ind = [0] * (len(g) + 1) # SInce oth Index is ignored
+ ind = [0] * (len(g) + 1) # Since 0th Index is ignored
for u in g:
for v in g[u]:
ind[v] += 1
@@ -166,15 +186,15 @@ def topo(g, ind=None, q=None):
for i in g:
if ind[i] == 0:
q.append(i)
- if len(q) == 0:
- return
- v = q.popleft()
- print(v)
- for w in g[v]:
- ind[w] -= 1
- if ind[w] == 0:
- q.append(w)
- topo(g, ind, q)
+ result = []
+ while q:
+ v = q.popleft()
+ result.append(v)
+ for w in g[v]:
+ ind[w] -= 1
+ if ind[w] == 0:
+ q.append(w)
+ return result[::-1] # Reverse the result list before returning
"""
@@ -375,3 +395,8 @@ def find_isolated_nodes(graph):
if not graph[node]:
isolated.append(node)
return isolated
+
+
+if __name__ == "__main__":
+ import doctest
+ doctest.testmod()
From 8151db7cc9e28e5a0f4ba70f4fb11149a6af3176 Mon Sep 17 00:00:00 2001
From: "pre-commit-ci[bot]"
<66853113+pre-commit-ci[bot]@users.noreply.github.com>
Date: Thu, 31 Oct 2024 03:40:38 +0000
Subject: [PATCH 2/2] [pre-commit.ci] auto fixes from pre-commit.com hooks
for more information, see https://pre-commit.ci
---
graphs/basic_graphs.py | 1 +
1 file changed, 1 insertion(+)
diff --git a/graphs/basic_graphs.py b/graphs/basic_graphs.py
index 22b30ad8ff38..132f1c55f88a 100644
--- a/graphs/basic_graphs.py
+++ b/graphs/basic_graphs.py
@@ -399,4 +399,5 @@ def find_isolated_nodes(graph):
if __name__ == "__main__":
import doctest
+
doctest.testmod()