解决此问题的一种方法是使用dictionary，使用tuple 的组合键和数据类型bool 的匹配值。
Dictionary<Tuple<string, string>, bool>
复合键 Tuple<sring,string> 将包含参与者的每个排列，并将它们与相应的 bool 值相匹配。
例如，字典中填充的值如：
Dictionary<Tuple<"Judith","James">, true>
...将表明 Judith 选择 James 是有效的。
因此，让我们为每个可能的参与者组合创建一个字典，并将它们的值设置为true，以便它们在程序开始时有效。
这可以通过cartesian join using an array with itself 来完成。
Dictionary<Tuple<string, string>, bool> dictionary = participants.SelectMany(left => participants, (left, right) => new Tuple<string, string>(left, right)).ToDictionary(item=> item, item=>true);
在获取所有可能选择的排列并将它们设置为 true 之后，我们可以通过“不允许选择”列表并将该复合键的字典值更改为 false。
dictionary[new Tuple<string, string>(personNotAllowing, notAllowedPerson)] = false;
您可以通过以下方式使用循环将参与者从选择中移除：
for(int abc=0;abc<participants.Length;abc++)
{
//remove clone set
Tuple<string, string> clonePair = Tuple.Create(participants[abc], participants[abc]);
dictionary.Remove(clonePair);
}
或者只需将克隆对的值更改为 false。
for(int abc=0;abc<participants.Length;abc++)
{
dictionary[Tuple.Create(participants[abc],participants[abc])] = false;
}
在这个示例程序中，我为参与者创建了一个string[]，并为他们不允许的相应人员列表创建了一个string[]。然后我执行笛卡尔连接，参与者数组与本身。这导致每个排列都有一个初始的true 布尔值。
我将不允许参与者的字典更改为假，并显示示例字典。
之后，我创建了 10 个随机参与者实例，这些参与者正在挑选其他随机参与者并测试它是否有效。
每次参与者选择另一个参与者时，我都会检查该复合键以查看其值是否为 true。
如果确实产生了有效的选择，那么结果参与者被选择的每个组合都被设置为false。
for(int j=0; j<participants.Length;j++)
{
//Make the partner never be able to be picked again
Tuple<string, string> currentPair2 = Tuple.Create(partner, participants[j]);
try
{
dictionary[currentPair2] = false;
}
catch
{
}
}
通过运行代码可以更好地说明这个概念。
演示：
static void Main(string[] args)
{
//Create participants set
string[] participants = {"James","John","Tyrone","Rebecca","Tiffany","Judith"};
//Create not allowed lists
string[] jamesNotAllowedList = {"Tiffany", "Tyrone"};
string[] johnNotAllowedList = {};
string[] tyroneNotAllowedList = {};
string[] rebeccaNotAllowedList ={"James", "Tiffany"};
string[] judithNotAllowedList = {};
//Create list of not allowed lists
string[][] notAllowedLists = { jamesNotAllowedList, johnNotAllowedList, tyroneNotAllowedList, rebeccaNotAllowedList, judithNotAllowedList};
//Create dictionary<Tuple<string,string>, bool> from participants array by using cartesian join on itself
Dictionary<Tuple<string, string>, bool> dictionary = participants.SelectMany(left => participants, (left, right) => new Tuple<string, string>(left, right)).ToDictionary(item=> item, item=>true);
//Loop through each person who owns a notAllowedList
for (int list = 0; list < notAllowedLists.Length; list++)
{
//Loop through each name on the not allowed list
for (int person = 0; person<notAllowedLists[list].Length; person++)
{
string personNotAllowing = participants[list];
string notAllowedPerson = notAllowedLists[list][person];
//Change the boolean value matched to the composite key
dictionary[new Tuple<string, string>(personNotAllowing, notAllowedPerson)] = false;
Console.WriteLine(personNotAllowing + " did not allow " + notAllowedPerson);
}
}
//Then since a participant cant pick itself
for(int abc=0;abc<participants.Length;abc++)
{
//remove clone set
Tuple<string, string> clonePair = Tuple.Create(participants[abc], participants[abc]);
dictionary.Remove(clonePair);
}
//Display whats going on with this Dictionary<Tuple<string,string>, bool>
Console.WriteLine("--------Allowed?--Dictionary------------\n");
Console.WriteLine(string.Join(" \n", dictionary));
Console.WriteLine("----------------------------------------\n\n");
//Create Random Object
Random rand = new Random();
//Now that the data is organized in a dictionary..
//..Let's have random participants pick random participants
//For this demonstration lets try it 10 times
for (int i=0;i<20;i++)
{
//Create a new random participant
int rNum = rand.Next(participants.Length);
string randomParticipant = participants[rNum];
//Random participant picks a random participant
string partner = participants[rand.Next(participants.Length)];
//Create composite key for the current pair
Tuple<string, string> currentPair = Tuple.Create(partner,randomParticipant);
//Check if it's a valid choice
try
{
if (dictionary[currentPair])
{
Console.WriteLine(randomParticipant + " tries to pick " + partner);
Console.WriteLine("Valid.\n");
//add to dictionary
for(int j=0; j<participants.Length;j++)
{
//Make the partner never be able to be picked again
Tuple<string, string> currentPair2 = Tuple.Create(partner, participants[j]);
try
{
dictionary[currentPair2] = false;
}
catch
{
}
}
}
else
{
Console.WriteLine(randomParticipant + " tries to pick " + partner);
Console.WriteLine(">>>>>>>>Invalid.\n");
}
}
catch
{
//otherwise exception happens because the random participant
//And its partner participant are the same person
//You can also handle the random participant picking itself differently
//In this catch block
//Make sure the loop continues as many times as necessary
//by acting like this instance never existed
i = i - 1;
}
}
Console.ReadLine();
}