find_longest_common_prefix precomputing

Author: PratiAmalden

Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py

@@ -1,24 +1,28 @@
 from typing import List
 
 
-def find_longest_common_prefix(strings: List[str]):
+def find_longest_common_prefix(strings: List[str]) -> str:
     """
     find_longest_common_prefix returns the longest string common at the start of any two strings in the passed list.
 
     In the event that an empty list, a list containing one string, or a list of strings with no common prefixes is passed, the empty string will be returned.
     """
+
+    if not strings or len(strings) < 2:
+        return ""
+
+    # Precompute sorted strings
+    sorted_strings = sorted(strings)
     longest = ""
-    for string_index, string in enumerate(strings):
-        for other_string in strings[string_index+1:]:
-            common = find_common_prefix(string, other_string)
-            if len(common) > len(longest):
-                longest = common
-    return 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]
 
-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]
+    return longest