From 7b098296ee650e3b50e1cf557ac8dc365d923824 Mon Sep 17 00:00:00 2001 From: Fatma Date: Sat, 17 Jan 2026 21:41:30 +0000 Subject: [PATCH 1/2] Optimise common_prefix: sort list to compare only neighbours --- .../common_prefix/common_prefix.py | 22 ++++++++++++++----- 1 file changed, 17 insertions(+), 5 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..5210b78 100644 --- a/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py +++ b/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py @@ -7,12 +7,24 @@ 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. """ + # If list is empty or has 1 item, no pairs exist. + if len(strings) < 2: + return "" + + 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 + + # We only need to compare neighbours. + for i in range(len(strings) - 1): + first_string = strings[i] + second_string = strings[i + 1] + + common = find_common_prefix(first_string, second_string) + + if len(common) > len(longest): + longest = common + return longest From ba73a63739769b33ff6b5e654172e9c679262fc0 Mon Sep 17 00:00:00 2001 From: Fatma Date: Sat, 17 Jan 2026 21:43:11 +0000 Subject: [PATCH 2/2] Optimise count_letters: use Set for instant lookups --- .../count_letters/count_letters.py | 21 ++++++++++--------- 1 file changed, 11 insertions(+), 10 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..a17fd8d 100644 --- a/Sprint-2/improve_with_precomputing/count_letters/count_letters.py +++ b/Sprint-2/improve_with_precomputing/count_letters/count_letters.py @@ -2,13 +2,14 @@ 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() - for letter in s: - if is_upper_case(letter): - if letter.lower() not in s: - only_upper.add(letter) - return len(only_upper) - - -def is_upper_case(letter: str) -> bool: - return letter == letter.upper() + # Create a Set of all characters in the string. + present_chars = set(s) + + only_upper_count = 0 + # We loop through the unique characters + for char in present_chars: + if char.isupper(): + if char.lower() not in present_chars: + only_upper_count += 1 + + return only_upper_count