如何在Ruby中检查数组中的范围?

时间:2015-04-13 05:17:46

标签: ruby arrays

我正在写一个扑克计划,我无法弄清楚如何处理直道。

直接:5张牌中的所有牌都是连续值。 恩。 2..6,3..7,4..8,5..9,6..T,7..J,8..Q,9..K,T..A

cards = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]

如何检查这些组合的手,这是一个数组?我最好能检查它是否在卡阵列中连续5行。

7 个答案:

答案 0 :(得分:4)

如果我们将每张卡映射到一个值(9是9," T"是10," J"是11等),那么有两个事实是真的我们可以用来解决问题的所有直道:

  1. 所有直道都有五个独特的卡片值
  2. 最后一张牌和第一张牌之间的差异'值总是4
  3. 所以:

    CARD_VALUES = {
        2 =>  2,    3 =>  3,    4 =>  4,
        5 =>  5,    6 =>  6,    7 =>  7,
        8 =>  8,    9 =>  9,  "T" => 10,
      "J" => 11,  "Q" => 12,  "K" => 13,
      "A" => 14
    }
    
    def is_straight?(hand)
      hand_sorted = hand.map {|card| CARD_VALUES[card] }
        .sort.uniq
    
      hand_sorted.size == 5 &&
        (hand_sorted.last - hand_sorted.first) == 4
    end
    

    此方法(1)使用map将每张卡转换为数字值,然后将(2)sort转换为它们,然后(3)使用uniq抛出重复项。用各种手来说明:

        hand |  4   A   T   A   2 |  2   2   3   3   4 |  5   6   4   8   7 |  3  6  2  8  7
    ---------+--------------------+--------------------+--------------------+----------------
     1. map  |  4  14  10  14   2 |  2   2   3   3   4 |  5   6   4   8   7 |  3  6  2  8  7
     2. sort |  2   4  10  14  14 |  2   2   3   3   4 |  4   5   6   7   8 |  2  3  6  7  8
     3. uniq |  2   4  10  14     |  2   3   4         |  4   5   6   7   8 |  2  3  6  7  8
    

    另外...

    我最初发布了以下解决方案,这不是很糟糕,但肯定更复杂:

    如果手被分类,这很容易。您可以使用Enumerable#each_cons检查每个可能的直线。

    CARDS = [ 2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A" ]
    hand = [ 4, 5, 6, 7, 8 ]
    
    def is_straight?(hand)
      CARDS.each_cons(5).any? do |straight|
        hand == straight
      end
    end
    
    if is_straight?(hand)
      puts "Straight!"
    else
      puts "Not straight!"
    end
    # => Straight!
    

    each_cons(5)会返回每组连续的5个项目,因此在上面的示例中,hand首先与[ 2, 3, 4, 5, 6 ]进行比较,然后是[ 3, 4, 5, 6, 7 ],然后是[ 4, 5, 6, 7, 8 ] ,这是匹配,因此any?会返回true

    请注意,这不是最有效的解决方案,但除非您需要每秒检查数千手牌,否则这不仅具有足够的效果。

    如果你的手还没有排序,你需要先做。最简单的方法是创建一个Hash,将卡映射到数值(如上所示),然后使用sort_by

    def sort_hand(hand)
      hand.sort_by {|card| CARD_VALUES[card] }
    end
    
    hand = [ 4, "A", 2, "A", "T" ]
    sort_hand(hand)
    # => [ 2, 4, "T", "A", "A" ]
    

答案 1 :(得分:4)

编辑2:这是我绝对的最终解决方案:

require 'set'
STRAIGHTS = ['A',*2..9,'T','J','Q','K','A'].each_cons(5).map(&:to_set)
  #=> [#<Set: {"A", 2, 3, 4, 5}>, #<Set: {2, 3, 4, 5, 6}>,
  #   ...#<Set: {9, "T", "J", "Q", "K"}>, #<Set: {"T", "J", "Q", "K", "A"}>]

def straight?(hand)
  STRAIGHTS.include?(hand.to_set)
end

STRAIGHTS.include?([6,3,4,5,2].to_set)
  # STRAIGHTS.include?(#<Set: {6, 3, 4, 5, 2}>)
  #=> true 

straight?([6,5,4,3,2])            #=> true 
straight?(["T","J","Q","K","A"])  #=> true 
straight?(["A","K","Q","J","T"])  #=> true
straight?([2,3,4,5,"A"])          #=> true 

straight?([6,7,8,9,"J"])          #=> false 
straight?(["J",7,8,9,"T"])        #=> false 

修改1: @mudasobwa通过指出'A',2,3,4,5是有效的直线来扰乱苹果购物车。我相信我已经解决了问题。 (我相信他不会告诉我'K','A',2,3,4也是有效的。)

我建议如下:

CARDS     = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
STRAIGHTS = CARDS.each_cons(5).to_a
  #=>[[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8],
  #   [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"],
  #   [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"],
  #   ["T", "J", "Q", "K", "A"]] 

def straight?(hand)
  (hand.map {|c| CARDS.index(c)}.sort == [0,1,2,3,12]) ||
  STRAIGHTS.include?(hand.sort {|a,b| CARDS.index(a) <=> CARDS.index(b)})
end

答案 2 :(得分:1)

生成有效牌的清单:

valid_hands = cards[0..8].each_with_index.map{|b,i| cards[i..i+4]}
#=> [[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8], [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"], [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"], ["T", "J", "Q", "K", "A"]]

获得所有有效牌的清单后,您现在可以检查提供的牌是否在any?之内(有效牌):

if valid_hands.any? { |h| (h - hand).empty? } 
   puts "Valid hand"
else
   puts "Not Valid"
end

<强>更新

案例2, 3, 4, 5, "A"2, 3, 4, "K", "A"2, 3, "Q", "K", "A"2, "J", "Q", "K", "A"也被视为有效牌,按如下方式计算:

valid_hands = cards.each_with_index.map { |b,i| i < 9 ? cards[i..i+4] : cards[0..i-9] + cards[i..-1] }
# => [[2, 3, 4, 5, 6], [3, 4, 5, 6, 7], [4, 5, 6, 7, 8], [5, 6, 7, 8, 9], [6, 7, 8, 9, "T"], [7, 8, 9, "T", "J"], [8, 9, "T", "J", "Q"], [9, "T", "J", "Q", "K"], ["T", "J", "Q", "K", "A"], [2, "J", "Q", "K", "A"], [2, 3, "Q", "K", "A"], [2, 3, 4, "K", "A"], [2, 3, 4, 5, "A"]]

答案 3 :(得分:1)

我不想参与,但我不能保持沉默,看看周围所有这些过于复杂的解决方案。

hand = [2, 5, 7, 'A', 'J'].map(&:to_s)

'23456789TJQKA' =~ hand.sort_by{|hc| '23456789TJQKA'.index(hc)}.join ||
   'A23456789TJQK' =~ hand.sort_by{|hc| 'A23456789TJQK'.index(hc)}.join

以一种不蹩脚的硬编码方式:

suit = '23456789TJQKA'

suit =~ hand.sort_by{|hc| suit.index(hc)}.join ||
   suit.rotate(-1) =~ hand.sort_by{|hc| suit.rotate(-1).index(hc)}.join

答案 4 :(得分:1)

我建议编写代表卡片的课程(也可能是Deck和Hand)。瞄准这样的界面:

deck = Deck.new.shuffle!
hand = Hand.new(deck.draw 5)
hand.straight?
#=>false
puts hand
8♣ 8♦ T♠ 2♦ 7♦

功能的封装为您提供了可读性,并使其易于扩展(即适合)

这是一个更简单的版本,实现为单个Card类。我确实加了西装。

class Card
  include Enumerable #enables sorting
  attr_accessor :value, :suit

  @values = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
  @suits  = ["♣","♦","♥","♠"]

  def self.all
    @values.product(@suits).map{|c| Card.new c}
  end

  def self.straight?(cards)
    ["A", *@values].each_cons(5).include?(cards.map(&:value))
  end

  def self.flush?(cards)
    cards.map(&:suit).uniq.size == 1
  end

  def initialize(v)
    @value, @suit = *v
  end

  def <=>(other) #for sorting
    @values.index(value) <=> @values.index(other.value)
  end

  def to_s
    "#{value}#{suit}"
  end
end

这可以如下工作

deck = Card.all
puts deck
#=> 2♣ 2♦ 2♥ 2♠ 3♣ 3♦ 3♥ 3♠ 4♣ 4♦ 4♥ 4♠ 5♣ 5♦ 5♥ 5♠ 6♣ 6♦ 6♥ 6♠ 7♣ 7♦ 7♥ 7♠ 8♣ 8♦ 8♥ 8♠ 9♣ 9♦ 9♥ 9♠ T♣ T♦ T♥ T♠ J♣ J♦ J♥ J♠ Q♣ Q♦ Q♥ Q♠ K♣ K♦ K♥ K♠ A♣ A♦ A♥ A♠
hand = deck.sample 5
puts hand
#=> Q♥ 6♦ 2♣ T♠ Q♦
Card.straight?(hand)
#=>false

答案 5 :(得分:0)

第0步:让我们从一个空类开始

class CardUtils
end

步骤1:将卡的值存储在哈希

Hash允许快速参考卡片的值。

@@card_values = {
    'A' => 1,   2  => 2,   3  => 3, 4 => 4,  5 => 5,
     6  => 6,   7  => 7,   8  => 8, 9 => 9, 'T' => 10,
    'J' => 11, 'Q' => 12, 'K' => 13
}

因此,您可以简单地参考卡值。

@@card_values['A']
# => 1

@@card_values[8]
# => 8

第2步:对手进行排序

参考卡片值,将sort!方法应用于手。

def self.sort(hand)
    hand.sort {|x,y| @@card_values[x] <=> @@card_values[y]}
end
#  => ["A", 2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K"] 

步骤3:告知两张牌是否连续的功能

def self.is_consecutive(x, y)
    val_x = @@card_values[x]
    val_y = @@card_values[y]

    val_x == val_y - 1 || val_x + 13 == val_y
end
# is_consecutive('A', 2)
#  => true
# is_consecutive('K', 'A')
#  => true
# is_consecutive('A', 3)
#  => false

第4步:检查'直接'

可以通过简单的迭代完成。

def self.has_straight(hand)
    hand = sort(hand)

    max_consecutive_count = 0
    consecutive_count = 0

    hand.each_with_index do |curr, i|
        prev = hand[i - 1]

        if is_consecutive(prev, curr) then
            consecutive_count += 1
        else
            consecutive_count = 0
        end

        if consecutive_count > max_consecutive_count then
            max_consecutive_count = consecutive_count
        end
    end

    max_consecutive_count >= 5
end
# hand = [2, 3, 4, 5, 6, 7, 8, 9, "T", "J", "Q", "K", "A"]
# CardUtils.has_straight(hand)
#  => true

最终结果

class CardUtils
    @@card_values = {
        'A' => 1,   2  => 2,   3  => 3, 4 => 4,  5 => 5,
         6  => 6,   7  => 7,   8  => 8, 9 => 9, 'T' => 10,
        'J' => 11, 'Q' => 12, 'K' => 13
    }

    def self.is_consecutive(x, y)
        val_x = @@card_values[x]
        val_y = @@card_values[y]

        val_x == val_y - 1 || val_x + 13 == val_y
    end

    def self.sort(hand)
        hand.sort {|x,y| @@card_values[x] <=> @@card_values[y]}
    end

    def self.has_straight(hand)
        hand = sort(hand)

        max_consecutive_count = 0
        consecutive_count = 0

        hand.each_with_index do |curr, i|
            prev = hand[i - 1]

            if is_consecutive(prev, curr) then
                consecutive_count += 1
            else
                consecutive_count = 0
            end

            if consecutive_count > max_consecutive_count then
                max_consecutive_count = consecutive_count
            end
        end

        max_consecutive_count >= 5
    end
end

答案 6 :(得分:0)

这就是我写它的方式:

hand  = [3,4,5,2,'A']


def is_straight(hand)

  # No need to check further if we do not have 5 unique cards.
  return false unless hand.uniq.size == 5

  # Note the A at beginning AND end to count A as 1 or 14.
  list_of_straights = 'A23456789TJQKA'.chars.each_cons(5)

  sorted_hand = hand.map(&:to_s).sort

  list_of_straights.any? do |straight| 
    straight.sort==sorted_hand
  end

end

puts is_straight(hand) #=> true  

或者,如果您不喜欢所有排序,您可以将最后一部分交换到:

  hand_as_stings = hand.map(&:to_s)

  list_of_straights.any? do |straight| 
    (straight-hand_as_stings).empty?
  end