problems

problems/medium/word-frequency/solution.py

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+"""
+Word Frequency Counter
+
+You're building a text analytics tool for a content marketing team.
+Given a block of text, return the top N most frequently used words,
+sorted by frequency (highest first), then alphabetically for ties.
+
+Example 1:
+    Input: text = "the quick brown fox jumps over the lazy dog the fox"
+           n = 2
+    Output: [("the", 3), ("fox", 2)]
+    Explanation: "the" appears 3 times, "fox" appears 2 times
+
+Example 2:
+    Input: text = "hello world hello"
+           n = 5
+    Output: [("hello", 2), ("world", 1)]
+    Explanation: Only 2 unique words, return all of them
+
+Constraints:
+    - Words are separated by whitespace
+    - Case-insensitive (convert to lowercase)
+    - Ignore punctuation attached to words
+    - n >= 1
+    - If fewer than n unique words exist, return all of them
+"""
+
+
+def top_words(text: str, n: int) -> list[tuple[str, int]]:
+    """Return top n words by frequency as list of (word, count) tuples."""
+    pass  # Your implementation here
+

problems/medium/word-frequency/tests.py

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+"""Tests for word-frequency."""
+import pytest
+from solution import top_words
+
+
+class TestBasicCases:
+    """Test basic functionality with typical inputs."""
+
+    def test_basic_frequency(self):
+        """Test basic word counting."""
+        result = top_words("the quick brown fox jumps over the lazy dog the fox", 2)
+        assert result == [("the", 3), ("fox", 2)]
+
+    def test_all_unique(self):
+        """Test when all words are unique."""
+        result = top_words("one two three", 2)
+        assert result == [("one", 1), ("three", 1)] or result == [("one", 1), ("two", 1)]
+
+    def test_single_word_repeated(self):
+        """Test with one word repeated."""
+        result = top_words("hello hello hello", 1)
+        assert result == [("hello", 3)]
+
+
+class TestEdgeCases:
+    """Test edge cases and boundary conditions."""
+
+    def test_empty_string(self):
+        """Test with empty input."""
+        result = top_words("", 5)
+        assert result == []
+
+    def test_n_greater_than_unique_words(self):
+        """Test when n exceeds unique word count."""
+        result = top_words("hello world", 10)
+        assert len(result) == 2
+
+    def test_case_insensitive(self):
+        """Test that counting is case-insensitive."""
+        result = top_words("Hello HELLO hello", 1)
+        assert result == [("hello", 3)]
+
+    def test_punctuation_ignored(self):
+        """Test that punctuation is stripped."""
+        result = top_words("hello, world! hello.", 1)
+        assert result == [("hello", 2)]
+
+    def test_alphabetical_tiebreaker(self):
+        """Test alphabetical ordering for same frequency."""
+        result = top_words("cat bat ant", 3)
+        assert result == [("ant", 1), ("bat", 1), ("cat", 1)]
+