Use find_common_prefix helper as suggested

Author: PratiAmalden

Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py

@@ -1,7 +1,7 @@
 from typing import List
 
 
-def find_longest_common_prefix(strings: List[str]) -> str:
+def find_longest_common_prefix(strings: List[str]):
     """
     find_longest_common_prefix returns the longest string common at the start of any two strings in the passed list.
 
@@ -16,13 +16,16 @@ def find_longest_common_prefix(strings: List[str]) -> str:
     longest = ""
 
     for i in range(len(sorted_strings) - 1):
-        s1, s2 = sorted_strings[i], sorted_strings[i + 1]
-        # Find common prefix between them
-        prefix_len = 0
-        max_len = min(len(s1), len(s2))
-        while prefix_len < max_len and s1[prefix_len] == s2[prefix_len]:
-            prefix_len += 1
-        if prefix_len > len(longest):
-            longest = s1[:prefix_len]
+        common = find_common_prefix(sorted_strings[i], sorted_strings[i + 1])
+        if len(common) > len(longest):
+            longest = common
 
     return longest
+
+
+def find_common_prefix(left: str, right: str) -> str:
+    min_length = min(len(left), len(right))
+    for i in range(min_length):
+        if left[i] != right[i]:
+            return left[:i]
+    return left[:min_length]