From daeab961eef7b91f823d110da87aebd314c18581 Mon Sep 17 00:00:00 2001
From: Case-y <personifyitdevs@gmail.com>
Date: Thu, 12 Mar 2026 17:11:52 -0400
Subject: [PATCH 1/2] Implement n=1 for .most_common

---
 Lib/collections/__init__.py  |  5 +++
 Lib/test/test_collections.py | 61 ++++++++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 2eee4c70955513..8aeafb35896299 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -634,6 +634,11 @@ def most_common(self, n=None):
         if n is None:
             return sorted(self.items(), key=_itemgetter(1), reverse=True)
 
+        if n == 1:
+            if not self.items():
+                return []
+            return [max(self.items(), key=_itemgetter(1))]        
+
         return _nlargest(n, self.items(), key=_itemgetter(1))
 
     def elements(self):
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index b1b2dd2ca5ca0d..9ddd7294aebed8 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -2134,6 +2134,67 @@ def test_basics(self):
         self.assertEqual(c['d'], 1)
         self.assertEqual(c.setdefault('e', 5), 5)
         self.assertEqual(c['e'], 5)
+    
+    def test_most_common_n_equals_one(self):
+        # Test n == 1 returns a list with one tuple
+        c1 = Counter('abcaba')
+        result = c1.most_common(1)
+        self.assertEqual(result, [('a', 3)])
+        self.assertIsInstance(result, list)
+        self.assertEqual(len(result), 1)
+        self.assertIsInstance(result[0], tuple)
+    
+        # Test n == 1 returns same format as other n values
+        self.assertEqual(c1.most_common(1), c1.most_common(2)[:1])
+    
+        # Test with a counter where all items have same count
+        c2 = Counter('abc')
+        result = c2.most_common(1)
+        self.assertEqual(len(result), 1)
+        self.assertIn(result[0][1], [1])  # count should be 1
+    
+        # Test n == 1 with single element
+        c3 = Counter('a')
+        self.assertEqual(c3.most_common(1), [('a', 1)])
+    
+        # Test n == 1 with empty counter
+        c4 = Counter()
+        self.assertEqual(c4.most_common(1), [])
+    
+        # Test that n == 1 and n == 2 are consistent at index 0
+        c5 = Counter('the quick brown fox')
+        one = c5.most_common(1)
+        two = c5.most_common(2)
+        self.assertEqual(one[0], two[0])
+
+        # Test n == 1 with negative counts
+        c6 = Counter({'a': -3, 'b': -1, 'c': 5})
+        self.assertEqual(c6.most_common(1), [('c', 5)])
+
+        # Test n == 1 with zero counts mixed in
+        c7 = Counter({'x': 0, 'y': 0, 'z': 1})
+        self.assertEqual(c7.most_common(1), [('z', 1)])
+
+        # Test n == 1 consistency with most_common(None)[0]
+        c8 = Counter('abracadabra')
+        self.assertEqual(c8.most_common(1)[0], c8.most_common()[0])
+
+        # Test n == 1 with counter built from keyword args
+        c9 = Counter(cat=10, dog=3, bird=7)
+        self.assertEqual(c9.most_common(1), [('cat', 10)])
+
+        # Test n == 1 with counter built from mapping
+        c10 = Counter({'apple': 50, 'banana': 20, 'cherry': 30})
+        self.assertEqual(c10.most_common(1), [('apple', 50)])
+
+        # Test n == 1 with large number of unique keys
+        c11 = Counter({i: i for i in range(1000)})
+        self.assertEqual(c11.most_common(1), [(999, 999)])
+
+        # Test n == 1 with a Counter subclass
+        c12 = CounterSubclassWithSetItem('aabbbc')
+        result = c12.most_common(1)
+        self.assertEqual(result, [('b', 3)])
 
     def test_update_reentrant_add_clears_counter(self):
         c = Counter()

From 0dac6d43c5160d8e80261ca7638e82d6033d45c3 Mon Sep 17 00:00:00 2001
From: Case-y <personifyitdevs@gmail.com>
Date: Thu, 12 Mar 2026 21:58:27 -0400
Subject: [PATCH 2/2] Fix lints

---
 Lib/collections/__init__.py  |  2 +-
 Lib/test/test_collections.py | 12 ++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 8aeafb35896299..3db851a3850dc1 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -637,7 +637,7 @@ def most_common(self, n=None):
         if n == 1:
             if not self.items():
                 return []
-            return [max(self.items(), key=_itemgetter(1))]        
+            return [max(self.items(), key=_itemgetter(1))]
 
         return _nlargest(n, self.items(), key=_itemgetter(1))
 
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 9ddd7294aebed8..686b102149dd25 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -2134,7 +2134,7 @@ def test_basics(self):
         self.assertEqual(c['d'], 1)
         self.assertEqual(c.setdefault('e', 5), 5)
         self.assertEqual(c['e'], 5)
-    
+
     def test_most_common_n_equals_one(self):
         # Test n == 1 returns a list with one tuple
         c1 = Counter('abcaba')
@@ -2143,24 +2143,24 @@ def test_most_common_n_equals_one(self):
         self.assertIsInstance(result, list)
         self.assertEqual(len(result), 1)
         self.assertIsInstance(result[0], tuple)
-    
+
         # Test n == 1 returns same format as other n values
         self.assertEqual(c1.most_common(1), c1.most_common(2)[:1])
-    
+
         # Test with a counter where all items have same count
         c2 = Counter('abc')
         result = c2.most_common(1)
         self.assertEqual(len(result), 1)
         self.assertIn(result[0][1], [1])  # count should be 1
-    
+
         # Test n == 1 with single element
         c3 = Counter('a')
         self.assertEqual(c3.most_common(1), [('a', 1)])
-    
+
         # Test n == 1 with empty counter
         c4 = Counter()
         self.assertEqual(c4.most_common(1), [])
-    
+
         # Test that n == 1 and n == 2 are consistent at index 0
         c5 = Counter('the quick brown fox')
         one = c5.most_common(1)