diff --git a/README.md b/README.md index fb63c1ea..4717d100 100644 --- a/README.md +++ b/README.md @@ -653,3 +653,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/). | 233. Number of Digit One | [Link](https://leetcode.com/problems/number-of-digit-one/) | [Link](./lib/hard/233_number_of_digit_one.rb) | [Link](./test/hard/test_233_number_of_digit_one.rb) | | 239. Sliding Window Maximum | [Link](https://leetcode.com/problems/sliding-window-maximum/) | [Link](./lib/hard/239_sliding_window_maximum.rb) | [Link](./test/hard/test_239_sliding_window_maximum.rb) | | 297. Serialize and Deserialize Binary Tree | [Link](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/) | [Link](./lib/hard/297_serialize_and_deserialize_binary_tree.rb) | [Link](./test/hard/test_297_serialize_and_deserialize_binary_tree.rb) | +| 336. Palindrome Pairs | [Link](https://leetcode.com/problems/palindrome-pairs/) | [Link](./lib/hard/336_palindrome_pairs.rb) | [Link](./test/hard/test_336_palindrome_pairs.rb) | diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec index 9bd2208e..ad6f6f56 100644 --- a/leetcode-ruby.gemspec +++ b/leetcode-ruby.gemspec @@ -5,7 +5,7 @@ require 'English' ::Gem::Specification.new do |s| s.required_ruby_version = '>= 3.0' s.name = 'leetcode-ruby' - s.version = '7.8.3' + s.version = '7.8.4' s.license = 'MIT' s.files = ::Dir['lib/**/*.rb'] + %w[README.md] s.executable = 'leetcode-ruby' diff --git a/lib/hard/336_palindrome_pairs.rb b/lib/hard/336_palindrome_pairs.rb new file mode 100644 index 00000000..8cbece0f --- /dev/null +++ b/lib/hard/336_palindrome_pairs.rb @@ -0,0 +1,49 @@ +# frozen_string_literal: true + +# https://leetcode.com/problems/palindrome-pairs/ +# @param {String[]} words +# @return {Integer[][]} +def palindrome_pairs(words) + result = [] + + word_map = words.each_with_index.to_h + + words.each_with_index do |word, index| + valid_prefixes, valid_suffixes = get_partials(word) + + valid_prefixes.each do |prefix| + reverse = prefix.reverse + + next unless word_map[reverse] && index != word_map[reverse] + + result << [index, word_map[reverse]] + end + + valid_suffixes.each do |suffix| + reverse = suffix.reverse + + result << [word_map[reverse], index] if word_map[reverse] && index != word_map[reverse] + end + end + + result.uniq +end + +private + +# @param {String} word +# @return {Integer[]} +def get_partials(word) + valid_prefixes = [] + valid_suffixes = [] + + (0..word.length).each do |i| + prefix = word.slice(0, i) + suffix = word.slice(i, word.size) + + valid_prefixes << prefix if suffix == suffix.reverse + valid_suffixes << suffix if prefix == prefix.reverse + end + + [valid_prefixes, valid_suffixes] +end diff --git a/test/hard/test_336_palindrome_pairs.rb b/test/hard/test_336_palindrome_pairs.rb new file mode 100644 index 00000000..3c5752e9 --- /dev/null +++ b/test/hard/test_336_palindrome_pairs.rb @@ -0,0 +1,45 @@ +# frozen_string_literal: true + +require_relative '../test_helper' +require_relative '../../lib/hard/336_palindrome_pairs' +require 'minitest/autorun' + +class PalindromePairsTest < ::Minitest::Test + def test_default_one + assert_equal( + [ + [0, 1], + [1, 0], + [3, 2], + [2, 4] + ], + palindrome_pairs( + %w[abcd dcba lls s sssll] + ) + ) + end + + def test_default_two + assert_equal( + [ + [0, 1], + [1, 0] + ], + palindrome_pairs( + %w[bat tab cat] + ) + ) + end + + def test_default_three + assert_equal( + [ + [0, 1], + [1, 0] + ], + palindrome_pairs( + ['a', ''] + ) + ) + end +end