thảo luận Leetcode mỗi ngày

defmodule Solution do
  def bag_of_tokens_score(tokens, power) do
    play(
      tokens |> Enum.sort(),
      tokens |> Enum.sort(:desc),
      power,
      tokens |> Enum.count(),
      0,
      0
    )
  end
  defp play(_up, _down, _power, n, played, score) when played == n, do: score
  defp play([cost | c_rest] = up, [restore | r_rest] = down, power, n, played, score) do
    cond do
      power >= cost -> play(c_rest, down, power - cost, n, played + 1, score + 1)
      score == 0 or played == n - 1 -> score
      true -> play(up, r_rest, power + restore, n, played + 1, score - 1)
    end
  end
end

class Solution:
    def bagOfTokensScore(self, tokens: List[int], power: int) -> int:
        tokens=sorted(tokens)
        left,right=0,len(tokens)-1
        score, res = 0, 0
        while left<=right and power>=tokens[left]:
            score+=1
            power-=tokens[left]
            left+=1
            res=max(res,score)
            while left<=right and power<tokens[left] and score>=1:
                power+=tokens[right]
                right-=1
                score-=1
        return res

class Solution:
    def bagOfTokensScore(self, tokens: List[int], power: int) -> int:
        tokens.sort()
        l, r = 0, len(tokens) - 1
        res, res_max = 0, 0

        while l <= r:
            while l <= r and power >= tokens[l]:
                power -= tokens[l]
                res += 1
                l += 1
               
            res_max = max(res_max, res)

            if res >= 1:
                res -= 1
                power += tokens[r]
                r -= 1
               
            if l <= r and res == 0 and power < tokens[l]:
                break
           
        return res_max

class Solution:
    def validUtf8(self, data: List[int]):
        def check_type(num):
            if 0 <= num <= 127:
                return 0
            elif num <= 191:
                return -1
            elif num <= 223:
                return 1
            elif num <= 239:
                return 2
            elif num <= 247:
                return 3
            else:
                return None

        remain = 0
        for num in data:
            tp = check_type(num)
            # print(remain, tp)
            if tp is None:
                return False
            if remain == 0 and tp < 0:
                return False
            elif remain > 0 and  tp >= 0:
                return False
            remain += tp
        
        if remain == 0:
            return True
        else:
            return False