LeetCode Permutation in String を解いた

久しぶりにleetcodeを使ってみた。UIが変わってたり間違えたテストケースを提出しないrunのテストケースに追加できるようになってたりして使いやすくなっていた。

問題

leetcode.com

解いた

# @param {String} s1
# @param {String} s2
# @return {Bolean}
def check_inclusion(s1, s2)
  chars = s1.chars.group_by(&:itself).transform_values { |num| num.count }
  targets = s2.chars
  start = false
  deleted = []

  targets.each_with_index do |target, index|
    return  true if chars.values.sum.zero?

    if chars.keys.include?(target) && !start
      chars[target] -= 1
      deleted << target
      start = true
    elsif !start
      next
    elsif start
      if !chars.keys.include?(target)
        start = false
        chars = s1.chars.group_by(&:itself).transform_values { |num| num.count }
        deleted = []
        next
      end

      if chars[target].zero?
        target_index = deleted.index(target)
        deleted[0..target_index].each do |target_str|
          chars[target_str] += 1
        end
        deleted = deleted[(target_index + 1)..]
        deleted << target
        chars[target] -= 1
        next
      end

      chars[target] -= 1
      deleted << target
    end
  end

  chars.values.sum.zero?
end