refactor: precomputing prefixes for faster lookup.

Author: AhmadHmedann

Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py

@@ -7,18 +7,14 @@ def find_longest_common_prefix(strings: List[str]):
 
     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.
     """
+    seen = set()
     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  string in strings:
+        for i in range(1,len(string)+1) :
+            prefix = string[:i]
+            if prefix in seen and len(prefix) > len(longest):
+                longest = prefix
 
+            seen.add(prefix)
+    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]