From 8fc0bbf00ce4587253d1e239ad453b0beef3a614 Mon Sep 17 00:00:00 2001
From: ivan <ivan1016017@gmail.com>
Date: Sat, 27 Sep 2025 04:41:14 -0600
Subject: [PATCH] algo passes all unit tests with coverage at 100%

---
 .../longest_common_prefix.py                  | 21 +++++++++++++++++
 .../test_longest_common_prefix_round_20.py    | 23 +++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 src/my_project/interviews/top_150_questions_round_20/longest_common_prefix.py
 create mode 100644 tests/test_150_questions_round_20/test_longest_common_prefix_round_20.py

diff --git a/src/my_project/interviews/top_150_questions_round_20/longest_common_prefix.py b/src/my_project/interviews/top_150_questions_round_20/longest_common_prefix.py
new file mode 100644
index 00000000..1adcd44c
--- /dev/null
+++ b/src/my_project/interviews/top_150_questions_round_20/longest_common_prefix.py
@@ -0,0 +1,21 @@
+from typing import List, Union, Collection, Mapping, Optional
+from abc import ABC, abstractmethod
+
+class Solution:
+    def longestCommonPrefix(self, strs: List[str]) -> str:
+
+        if not strs:
+            return ''
+        else: 
+            min_strs, max_strs = min(strs), max(strs)
+            count = 0
+
+            len_min_strs = len(min_strs)
+
+            for i in range(len_min_strs):
+                if min_strs[i] != max_strs[i]:
+                    break
+                else: 
+                    count += 1
+
+            return min_strs[:count]
diff --git a/tests/test_150_questions_round_20/test_longest_common_prefix_round_20.py b/tests/test_150_questions_round_20/test_longest_common_prefix_round_20.py
new file mode 100644
index 00000000..91682ce9
--- /dev/null
+++ b/tests/test_150_questions_round_20/test_longest_common_prefix_round_20.py
@@ -0,0 +1,23 @@
+import unittest
+from src.my_project.interviews.top_150_questions_round_20\
+.longest_common_prefix import Solution
+
+class LongestCommonPrefixTestCase(unittest.TestCase):
+
+    def test_longest_common_prefix(self):
+        solution = Solution()
+        output = solution.longestCommonPrefix(strs=["flower","flow","flight"])
+        target = 'fl'
+        self.assertEqual(target, output)
+
+    def test_longest_no_common_prefix(self):
+        solution = Solution()
+        output = solution.longestCommonPrefix(strs=["dog","racecar","car"])
+        target = ''
+        self.assertEqual(target, output)
+
+    def test_longest_common_prefix_null_list(self):
+        solution = Solution()
+        output = solution.longestCommonPrefix(strs=[])
+        target = ''
+        self.assertEqual(target, output)
\ No newline at end of file