From 27548206cc384393ddaf5e1852fe4f7277f22973 Mon Sep 17 00:00:00 2001 From: Ahmad Hmedan Date: Sun, 4 Oct 2026 15:42:16 +0100 Subject: [PATCH 1/4] refactor: precomputing prefixes for faster lookup. --- .../common_prefix/common_prefix.py | 20 ++++++++----------- 1 file changed, 8 insertions(+), 12 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..2f57799 100644 --- a/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py +++ b/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] From 347b775b58f960bd06760e8738962592a047ea92 Mon Sep 17 00:00:00 2001 From: Ahmad Hmedan Date: Sun, 4 Oct 2026 16:02:43 +0100 Subject: [PATCH 2/4] refactor: precomputing unique letters for faster lookup --- .../count_letters/count_letters.py | 20 +++++++++++++++++-- 1 file changed, 18 insertions(+), 2 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..206da8d 100644 --- a/Sprint-2/improve_with_precomputing/count_letters/count_letters.py +++ b/Sprint-2/improve_with_precomputing/count_letters/count_letters.py @@ -1,11 +1,27 @@ +# 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() + 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: + unique_letters = set(s) + for letter in unique_letters: if is_upper_case(letter): - if letter.lower() not in s: + if letter.lower() not in unique_letters: only_upper.add(letter) return len(only_upper) From 7e39c41ffcb3d12dd327ceddb38c8d8d35b4d48b Mon Sep 17 00:00:00 2001 From: Ahmad Hmedan Date: Sun, 4 Oct 2026 16:04:17 +0100 Subject: [PATCH 3/4] chore: remove commented-out code --- .../count_letters/count_letters.py | 15 --------------- 1 file changed, 15 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 206da8d..d33b474 100644 --- a/Sprint-2/improve_with_precomputing/count_letters/count_letters.py +++ b/Sprint-2/improve_with_precomputing/count_letters/count_letters.py @@ -1,18 +1,3 @@ -# 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() - def count_letters(s: str) -> int: """ count_letters returns the number of letters which only occur in upper case in the passed string. From 526920314f55bbab79cfd58c81cb86c2eee10872 Mon Sep 17 00:00:00 2001 From: Ahmad Hmedan Date: Mon, 5 Oct 2026 21:33:44 +0100 Subject: [PATCH 4/4] style: format code --- .../improve_with_precomputing/common_prefix/common_prefix.py | 5 ++--- 1 file changed, 2 insertions(+), 3 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 2f57799..b9865a0 100644 --- a/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py +++ b/Sprint-2/improve_with_precomputing/common_prefix/common_prefix.py @@ -9,12 +9,11 @@ def find_longest_common_prefix(strings: List[str]): """ seen = set() longest = "" - for string in strings: - for i in range(1,len(string)+1) : + 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 -