From 4a53b30f8ffaa1b74ef8d57f30a24c249304d281 Mon Sep 17 00:00:00 2001 From: nadika Date: Thu, 12 Jun 2025 22:04:42 +0100 Subject: [PATCH 1/2] Improve common_prefix code --- .../common_prefix/common_prefix.py | 21 +++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py b/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py index f4839e7..5e0832d 100644 --- a/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py +++ b/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py @@ -1,18 +1,27 @@ 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 the list has less than 2 strings, we can return early (nothing to compare) + if len(strings) < 2: + return "" + #Sort strings to bring similar ones next to each other + # This helps to find common parts faster without checking every possible pair! + strings.sort() + 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 + + #instead of checking all pairs (that is slow), just check each pair of neighbors + 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 From d1aa7be4dbe9b8a2f205a99af478ef91808ffd74 Mon Sep 17 00:00:00 2001 From: nadika Date: Fri, 13 Jun 2025 12:37:57 +0100 Subject: [PATCH 2/2] Improve count_letters code --- .../count_letters/count_letters.py | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/Sprint-2/improve_with_precomputing/count_letters/count_letters.py b/Sprint-2/improve_with_precomputing/count_letters/count_letters.py index 62c3ec0..a3203e9 100644 --- a/Sprint-2/improve_with_precomputing/count_letters/count_letters.py +++ b/Sprint-2/improve_with_precomputing/count_letters/count_letters.py @@ -2,11 +2,22 @@ def count_letters(s: str) -> int: """ count_letters returns the number of letters which only occur in upper case in the passed string. """ - only_upper = set() + # Store all lowercase and uppercase letters from the string + # This helps to check faster later + lower_letters = set() + upper_letters = set() + + # Go through the string once and fill the sets for letter in s: if is_upper_case(letter): - if letter.lower() not in s: - only_upper.add(letter) + upper_letters.add(letter) + else: + lower_letters.add(letter) + + # Only keep uppercase letters that don't have lowercase versions + # Using sets makes this check much faster + only_upper = {letter for letter in upper_letters if letter.lower() not in lower_letters} + return len(only_upper)