Added BFS/DFS

README.md

@@ -8,8 +8,10 @@ A repo for storing Python code and tracking learning progress. All programs are
 .
 ├── README.md
 ├── algorithms
+│   ├── bfs.py
 │   ├── binary_search.py
 |   ├── bubble_sort.py
+|   ├── dfs.py
 |   ├── quicksort.py
 │   └── selection_sort.py
 ├── asynchronous_programming

algorithms/bfs.py

@@ -0,0 +1,48 @@
+from collections import deque
+
+
+def bfs(graph: dict[str, list[str]], start: str, target: str) -> bool:
+    return _bfs(graph, start, target, seen=set())
+
+
+def _bfs(
+        graph: dict[str, list[str]],
+        node: str,
+        target: str,
+        seen: set[str],
+        ) -> bool:
+
+    queue = deque([node])
+    seen.add(node)
+    while queue:
+        current = queue.popleft()
+        if current == target:
+            return True
+        for child in graph[current]:
+            if child not in seen:
+                seen.add(child)
+                queue.append(child)
+    return False
+
+
+def main() -> None:
+    graph = {
+            "(A)": ["(B)", "(C)"],
+            "(B)": ["(D)", "(E)"],
+            "(C)": ["(F)"],
+            "(D)": [],
+            "(E)": [],
+            "(F)": [],
+            }
+    start = "(A)"
+    target = "(F)"
+
+    found = bfs(graph, start, target)
+    if found:
+        print(f"Target {target} was found!")
+    else:
+        print(f"Target {target} was not found.")
+
+
+if __name__ == "__main__":
+    main()

algorithms/dfs.py

@@ -0,0 +1,42 @@
+def dfs(graph: dict[str, list[str]], start: str, target: str) -> bool:
+    return _dfs(graph, start, target, seen=set())
+
+
+def _dfs(
+        graph: dict[str, list[str]],
+        node: str,
+        target: str,
+        seen: set[str]
+        ) -> bool:
+
+    if node == target:
+        return True
+    seen.add(node)
+    for child in graph[node]:
+        if child not in seen:
+            if _dfs(graph, child, target, seen):
+                return True
+    return False
+
+
+def main() -> None:
+    graph = {
+            "(A)": ["(B)", "(C)"],
+            "(B)": ["(D)", "(E)"],
+            "(C)": ["(F)"],
+            "(D)": [],
+            "(E)": [],
+            "(F)": [],
+            }
+    start = "(A)"
+    target = "(F)"
+
+    found = dfs(graph, start, target)
+    if found:
+        print(f"Target {target} was found!")
+    else:
+        print(f"Target {target} was not found.")
+
+
+if __name__ == "__main__":
+    main()