London | 25-SDC-July | Eyuel Abraham | Sprint-2 | Improve_with_precomputing.

Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py

@@ -1,18 +1,26 @@
 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 len(strings) < 2:
+        return ""
+
+    # PRE-COMPUTE by sorting strings once
+    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
+
+    #compare only strings that are next to eacotherr in sorted order
+    for i in range(len(strings) - 1):
+        common = find_common_prefix(strings[i], strings[i + 1])
+        if len(common) > len(longest):
+            longest = common
+
     return longest