Arrays 数组洗牌后不重复结果

基本上，我有一个被洗牌的数组。阵列是一副卡片，例如：

var rank = ["A","2","3","4","5","6","7","8","9","10","J","Q","K"]
var suit = ["♠", "♥","♦","♣"]
var deck = [String]()

我有一个for循环来创建甲板

    for t in suit {
        for r in rank {
            deck.append("\(r)\(t)")
        }
    }

然后，我在一个函数中调用了一个扩展，我创建了这个扩展来洗牌牌。这给我带来了52张随机分类的卡片

        deck.shuffle()

唯一的问题是，虽然结果是随机的，但我不希望卡片重复。例如，如果结果为2♠, 我不想要两个♥, 2.♦, 2.♣ 下面是打印的列表

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感谢您的帮助！谢谢

我认为最好的方法是使用改进的Knuth shuffle。下面的代码是一个完整的示例。在customshuffle.swift中保存内容后，只需使用swiftc-o customshuffle customshuffle.swift&&./customshuffle在shell中运行它

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这可以很快地计算出来，这是合理的公平，但并非毫无偏见。我怀疑，如果您的约束运行得很快，可能很难生成一个公平的洗牌。

您是否考虑过再次洗牌，直到不再重复？有52个！=8.065 x 10^67洗牌的方法因此你洗牌的机会非常小是的，尽管发生的是UILabel打印了什么牌组。首先是，然后洗牌。我唯一的问题是，我从不希望洗牌后打印的顺序有重复。你真的不希望牌组洗牌？所以你永远不希望一张牌后面跟着另一张相同等级的牌？是的，基本上我想要洗牌，但结果不是相同等级的。谢谢你的回复！

import Foundation

let decksize = 52


let rankStrings = ["A","2","3","4","5","6","7","8","9","10","J","Q","K"]
let suitStrings = ["♠", "♥","♦","♣"]

struct card : Hashable, Equatable, CustomStringConvertible {
    var rank: Int //1,2...,11,12,13
    var suit: Int // 1,2,3,4

    var hashValue: Int {
      return rank + suit
    }
    static func == (lhs: card, rhs: card) -> Bool {
        return lhs.rank == rhs.rank && lhs.suit == rhs.suit
    }

    var description: String {
      return rankStrings[self.rank - 1] + suitStrings[self.suit - 1]
    }
}

// seems like Swift still lacks a portable random number generator
func portablerand(_ max: Int)->Int {
      #if os(Linux)
            return Int(random() % (max + 1)) // biased but I am in a hurry
       #else
            return Int(arc4random_uniform(UInt32(max)))
      #endif
}

// we populate a data structure where the
// cards are partitioned by rank and then suit (this is not essential)

var deck = [[card]]()
for i in 1...13 {
    var thisset = [card]()
    for j in 1...4 {
        thisset.append(card(rank:i,suit:j))
    }
    deck.append(thisset)
}

// we write answer in "answer"
var answer = [card]()
// we pick a card at random, first card is special
var rnd = portablerand(decksize)
answer.append(deck[rnd / 4].remove(at: rnd % 4))

while answer.count < decksize {
  // no matter what, we do not want to repeat this rank
  let lastrank = answer.last!.rank
  var myindices = [Int](deck.indices)
  myindices.remove(at: lastrank - 1)
  var totalchoice = 0
  var maxbag = -1
  for i in myindices {
      totalchoice = totalchoice + deck[i].count
      if  maxbag == -1 || deck[i].count  > deck[maxbag].count {
        maxbag = i
      }
  }
  if 2 * deck[maxbag].count >= totalchoice {
    // we have to pick from maxbag
    rnd = portablerand(deck[maxbag].count)
    answer.append(deck[maxbag].remove(at: rnd))
  } else {
    // any bag will do
    rnd = portablerand(totalchoice)
    for i in myindices {
        if rnd >= deck[i].count {
          rnd = rnd - deck[i].count
        } else {
          answer.append(deck[i].remove(at: rnd))
          break
        }
    }
  }
}


for card in answer {
  print(card)
}