Finds longest common prefix string amongst an array of strings

Author: BarthJr

longest_common_prefix.py

@@ -0,0 +1,33 @@
+# Write a function to find the longest common prefix string amongst an array of strings.
+# If there is no common prefix, return an empty string "".
+
+from typing import List
+from unittest import TestCase
+
+
+def longestCommonPrefix(strs: List[str]) -> str:
+    if not strs:
+        return ''
+    strs.sort()
+    min_strs, max_strs = strs[0], strs[-1]
+    for i, letter in enumerate(min_strs):
+        if max_strs[i] != letter:
+            return min_strs[:i]
+    return min_strs
+
+
+class TestsLongestCommonPrefix(TestCase):
+    def test_empty_list(self):
+        self.assertEqual('', longestCommonPrefix([]))
+
+    def test_with_one_element_in_list(self):
+        self.assertEqual('flower', longestCommonPrefix(["flower"]))
+
+    def test_simple_case(self):
+        self.assertEqual('fl', longestCommonPrefix(["flower", "flow", "flight"]))
+
+    def test_with_no_common_prefix(self):
+        self.assertEqual('', longestCommonPrefix(["dog", "racecar", "car"]))
+
+    def test_with_common_prefix(self):
+        self.assertEqual('a', longestCommonPrefix(["abcde", "abcdeea", "abc", "adbc"]))