Dfs

allalgorithms/graph/__init__.py

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+from .dfs import dfs_paths

allalgorithms/graph/dfs.py

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+# -*- coding: UTF-8 -*-
+#
+# find path from a node to another node using dfs algorithm.
+# The All ▲lgorithms library for python
+# Code credit: https://github.com/eddmann
+# Contributed by: glyphack
+# Github: @glyphack
+
+from typing import Dict, Union
+
+
+def dfs_paths(graph: Dict[str, set], start: str, destination: str) -> Union[list, None]:
+    stack = [(start, [start])]
+    while stack:
+        (vertex, path) = stack.pop()
+        for next in graph[vertex] - set(path):
+            if next == destination:
+                yield path + [next]
+            else:
+                stack.append((next, path + [next]))

docs/graph/dfs.md

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+# Depth first search
+
+[Depth-first search](https://en.wikipedia.org/wiki/Depth-first_search) (DFS) is an algorithm for traversing or searching tree or graph data structures. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible along each branch before backtracking.
+
+## Install
+
+```
+pip install allalgorithms
+```
+
+## Usage
+
+```py
+from allalgorithms.graph import dfs_path
+
+graph = {'A': set(['B', 'C']),
+         'B': set(['A', 'D', 'E']),
+         'C': set(['A', 'F']),
+         'D': set(['B']),
+         'E': set(['B', 'F']),
+         'F': set(['C', 'E'])}
+
+list(dfs_paths(graph, 'A', 'F'))
+# -> [['A', 'C', 'F'], ['A', 'B', 'E', 'F']]
+
+```
+
+## API
+
+def dfs_paths(graph: Dict[str, set], start: str, destination: str) -> Union[list, None]:
+
+> Return list of lists that contain path to destination from start, if there is not any returns `None`
+
+##### Params:
+
+- `graph`: Dictionary containing the graph to be searched
+- `start` : Name of the start node
+- `destination` : Name of the destination node

tests/test_graph.py

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+import unittest
+
+from allalgorithms.graph import dfs_paths
+
+
+class TestGraph(unittest.TestCase):
+    def setUp(self):
+        super().setUp()
+        self.test_graph = {
+            "A": set(["B", "C"]),
+            "B": set(["A", "D", "E"]),
+            "C": set(["A", "F"]),
+            "D": set(["B"]),
+            "E": set(["B", "F"]),
+            "F": set(["C", "E"]),
+        }
+
+    def test_dfs(self):
+        self.assertEqual([['A', 'B', 'E', 'F'], ['A', 'C', 'F']], list(dfs_paths(self.test_graph, 'A', 'F')))
+
+
+if __name__ == "__main__":
+    unittest.main()