From 1cf5ca9ec07e2c3c125f075c10b2ba713dbc7c7c Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Sat, 16 May 2020 23:36:25 -0500
Subject: Connected Components done!

---
 sources/connected_components.py    | 33 +++++++++++++++++++++++++++++++++
 tests/test_connected_components.py | 12 ++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 sources/connected_components.py
 create mode 100644 tests/test_connected_components.py

diff --git a/sources/connected_components.py b/sources/connected_components.py
new file mode 100644
index 0000000..f09f7dc
--- /dev/null
+++ b/sources/connected_components.py
@@ -0,0 +1,33 @@
+# Uses python3
+
+import sys
+
+
+def explore(adj, visited, v):
+    visited.append(v)
+    for i in adj[v]:
+        if i not in visited:
+            explore(adj, visited, i)
+
+
+def number_of_components(adj):
+    visited = []
+    cc = 0
+    for v in range(len(adj)):
+        if v not in visited:
+            explore(adj, visited, v)
+            cc = cc + 1
+    return cc
+
+
+if __name__ == '__main__':
+    input = sys.stdin.read()
+    data = list(map(int, input.split()))
+    n, m = data[0:2]
+    data = data[2:]
+    edges = list(zip(data[0:(2 * m):2], data[1:(2 * m):2]))
+    adj = [[] for _ in range(n)]
+    for (a, b) in edges:
+        adj[a - 1].append(b - 1)
+        adj[b - 1].append(a - 1)
+    print(number_of_components(adj))
diff --git a/tests/test_connected_components.py b/tests/test_connected_components.py
new file mode 100644
index 0000000..10d7a23
--- /dev/null
+++ b/tests/test_connected_components.py
@@ -0,0 +1,12 @@
+import unittest
+from sources.connected_components import number_of_components
+
+class MyTestCase(unittest.TestCase):
+    def test_something(self):
+        adj = [[1], [0, 2], [1], []]
+
+        self.assertEqual(2, number_of_components(adj))
+
+
+if __name__ == '__main__':
+    unittest.main()
-- 
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