From 15a7c36f9c7c8e25a91a88db381ac4c54f253e23 Mon Sep 17 00:00:00 2001
From: Tatiana Muromtseva <tamuromt@yandex.ru>
Date: Wed, 26 Nov 2025 22:20:24 +0300
Subject: [PATCH 1/4] Add depth-first search algorithm

---
 src/dfs.py | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 src/dfs.py

diff --git a/src/dfs.py b/src/dfs.py
new file mode 100644
index 0000000..ffc3d6b
--- /dev/null
+++ b/src/dfs.py
@@ -0,0 +1,37 @@
+class Graph:
+    def init(self):
+        self.adj = {}
+        self._dfs_order = None  # порядок обхода для итерации
+
+    def add_vertex(self, v):
+        if v not in self.adj:
+            self.adj[v] = []
+
+    def add_edge(self, u, v):
+        self.add_vertex(u)
+        self.add_vertex(v)
+        self.adj[u].append(v)
+        self.adj[v].append(u)
+
+    def dfs(self, start):
+        visited = set()
+        order = []
+
+        def _dfs(v):
+            visited.add(v)
+            order.append(v)
+            for nxt in self.adj[v]:
+                if nxt not in visited:
+                    _dfs(nxt)
+
+        _dfs(start)
+        self._dfs_order = order  # граф станет итерируемым в этом порядке
+        return order
+
+    def iter(self):
+        # итерируем граф в порядке последнего DFS
+        if self._dfs_order is None:
+            raise RuntimeError(
+                "Сначала нужно вызвать dfs(), чтобы определить порядок итерации"
+            )
+        return iter(self._dfs_order)

From d5391dbb2d7076b9fbedb6a2525f4d51234ddf44 Mon Sep 17 00:00:00 2001
From: Tatiana Muromtseva <tamuromt@yandex.ru>
Date: Wed, 26 Nov 2025 22:20:56 +0300
Subject: [PATCH 2/4] and test for it

---
 tests/test_dfs.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 tests/test_dfs.py

diff --git a/tests/test_dfs.py b/tests/test_dfs.py
new file mode 100644
index 0000000..5d2ed7e
--- /dev/null
+++ b/tests/test_dfs.py
@@ -0,0 +1,23 @@
+import pytest
+from src.dfs import Graph
+
+
+def test_dfs_order():
+    g = Graph()
+    g.add_edge(1, 2)
+    g.add_edge(1, 3)
+    g.add_edge(2, 4)
+    g.add_edge(2, 5)
+
+    result = g.dfs(1)
+    assert result == [1, 2, 4, 5, 3]
+
+
+def test_iteration_after_dfs():
+    g = Graph()
+    g.add_edge("A", "B")
+    g.add_edge("A", "C")
+    g.add_edge("B", "D")
+
+    order = g.dfs("A")
+    assert list(g) == order

From 4f5b9254840c63508a315b503777147ccb0e10fe Mon Sep 17 00:00:00 2001
From: Tatiana Muromtseva <tamuromt@yandex.ru>
Date: Mon, 8 Dec 2025 04:50:20 +0300
Subject: [PATCH 3/4] Pull workflow from CI branch

---
 .github/workflows/main.yml | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 .github/workflows/main.yml

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..56c2ac4
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,19 @@
+name: Ruff
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13.7"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff pytest
+      - name: Run Ruff
+        run: ruff check --output-format=github .
+      - name: Run unit-tests
+        run: python -m pytest tests/*

From 13a1c69ff8f4a9ce3afc67f692662a9b80917c67 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A2=D0=B0=D1=82=D1=8C=D1=8F=D0=BD=D0=B0=20=D0=9C=D1=83?=
 =?UTF-8?q?=D1=80=D0=BE=D0=BC=D1=86=D0=B5=D0=B2=D0=B0?= <tamuromt@yandex.ru>
Date: Wed, 17 Dec 2025 23:04:59 +0300
Subject: [PATCH 4/4] Update test_dfs.py

---
 tests/test_dfs.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/test_dfs.py b/tests/test_dfs.py
index 5d2ed7e..4c9610f 100644
--- a/tests/test_dfs.py
+++ b/tests/test_dfs.py
@@ -1,4 +1,3 @@
-import pytest
 from src.dfs import Graph