Add problem 763 - Partition Labels

Author: anirudhology

problems/greedy/partition_labels.py

@@ -0,0 +1,27 @@
+from typing import List
+
+
+class PartitionLabels:
+    @staticmethod
+    def partitionLabels(s: str) -> List[int]:
+        # List to store the sizes of partitions
+        sizes = []
+        # Special case
+        if not s:
+            return sizes
+
+        # Array to store last positions of characters
+        last_position = [0] * 26
+        for i in range(len(s)):
+            last_position[ord(s[i]) - ord('a')] = i
+
+        # Pointers for the window
+        left, right = 0, 0
+        # Traverse through the string again
+        for i in range(len(s)):
+            right = max(right, last_position[ord(s[i]) - ord('a')])
+            if right == i:
+                sizes.append(right - left + 1)
+                left = i + 1
+
+        return sizes

tests/greedy/partition_labels_test.py

@@ -0,0 +1,39 @@
+import unittest
+
+from problems.greedy.partition_labels import PartitionLabels
+
+
+class TestPartitionLabels(unittest.TestCase):
+
+    def setUp(self):
+        self.partition_labels = PartitionLabels()
+
+    def test_partition_labels(self):
+        # Test null input
+        self.assertEqual(self.partition_labels.partitionLabels(None), [])
+
+        # Test empty string
+        self.assertEqual(self.partition_labels.partitionLabels(""), [])
+
+        # Test string with all unique characters
+        self.assertEqual(self.partition_labels.partitionLabels("abcd"), [1, 1, 1, 1])
+
+        # Test string with all same characters
+        self.assertEqual(self.partition_labels.partitionLabels("aaaa"), [4])
+
+        # Test string with multiple partitions
+        self.assertEqual(self.partition_labels.partitionLabels("ababcbacadefegdehijhklij"), [9, 7, 8])
+
+        # Test string with overlapping partitions
+        self.assertEqual(self.partition_labels.partitionLabels("eababcbaca"), [1, 9])
+
+    def test_edge_cases(self):
+        # Test single character string
+        self.assertEqual(self.partition_labels.partitionLabels("a"), [1])
+
+        # Test string with repeating characters
+        self.assertEqual(self.partition_labels.partitionLabels("abacaba"), [7])
+
+
+if __name__ == '__main__':
+    unittest.main()