LeetCode/problems/word-pattern.rb

# @param {String} pattern
# @param {String} s
# @return {Boolean}
def word_pattern(pattern, s)
    words = s.split

    expected_words = Hash.new
    expected_patterns = Hash.new

    pattern.chars.zip(words).each { |pat, word|
        expected_word = expected_words[pat]
        expected_pattern = expected_patterns[word]

        if expected_pattern == nil && expected_word == nil then
            expected_patterns[word] = pat
            expected_words[pat] = word
        elsif word != expected_word || pat != expected_pattern then
            return false
        end
    }

    return pattern.size == words.size
end

RSpec.describe "word_pattern" do
    it "finds pattern" do
        expect(word_pattern("abba", "dog cat cat dog")).to be true
    end

    it "finds one odd word" do
        expect(word_pattern("abba", "dog cat cat fish")).to be false
    end

    it "finds that are not the same words" do
        expect(word_pattern("aaaa", "dog cat cat dog")).to be false
    end

    it "handles bijection correctly" do
        expect(word_pattern("abba", "dog dog dog dog")).to be false
    end

    it "handles correctly different length of input" do
        expect(word_pattern("aaa", "aa aa aa aa")).to be false
    end

    it "handles correctly different length of pattern" do
        expect(word_pattern("aaaaa", "aa aa aa aa")).to be false
    end
end