【发布时间】：2010-09-07 15:52:25
【问题描述】：
我创建了一个类（下面的代码）来处理在测试中创建“匹配”测验项目，这是输出：
效果很好。
但是，为了使其完全随机，我必须让 线程休眠 在两列的随机洗牌之间至少 300 个计数，任何低于 300 会返回以相同顺序排序的两列，就好像它使用相同的随机种子：
LeftDisplayIndexes.Shuffle();
Thread.Sleep(300);
RightDisplayIndexes.Shuffle();
我必须做些什么才能使两列的改组完全随机而无需等待？
完整代码：
using System.Collections.Generic;
using System;
using System.Threading;
namespace TestSort727272
{
class Program
{
static void Main(string[] args)
{
MatchingItems matchingItems = new MatchingItems();
matchingItems.Add("one", "111");
matchingItems.Add("two", "222");
matchingItems.Add("three", "333");
matchingItems.Add("four", "444");
matchingItems.Setup();
matchingItems.DisplayTest();
matchingItems.DisplayAnswers();
Console.ReadLine();
}
}
public class MatchingItems
{
public List<MatchingItem> Collection { get; set; }
public List<int> LeftDisplayIndexes { get; set; }
public List<int> RightDisplayIndexes { get; set; }
private char[] _numbers = { '1', '2', '3', '4', '5', '6', '7', '8' };
private char[] _letters = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h' };
public MatchingItems()
{
Collection = new List<MatchingItem>();
LeftDisplayIndexes = new List<int>();
RightDisplayIndexes = new List<int>();
}
public void Add(string leftText, string rightText)
{
MatchingItem matchingItem = new MatchingItem(leftText, rightText);
Collection.Add(matchingItem);
LeftDisplayIndexes.Add(Collection.Count - 1);
RightDisplayIndexes.Add(Collection.Count - 1);
}
public void DisplayTest()
{
Console.WriteLine("");
Console.WriteLine("--TEST:-------------------------");
for (int i = 0; i < Collection.Count; i++)
{
int leftIndex = LeftDisplayIndexes[i];
int rightIndex = RightDisplayIndexes[i];
Console.WriteLine("{0}. {1,-12}{2}. {3}", _numbers[i], Collection[leftIndex].LeftText, _letters[i], Collection[rightIndex].RightText);
}
}
public void DisplayAnswers()
{
Console.WriteLine("");
Console.WriteLine("--ANSWERS:-------------------------");
for (int i = 0; i < Collection.Count; i++)
{
string leftLabel = _numbers[i].ToString();
int leftIndex = LeftDisplayIndexes[i];
int rightIndex = RightDisplayIndexes.IndexOf(leftIndex);
string answerLabel = _letters[rightIndex].ToString();
Console.WriteLine("{0}. {1}", leftLabel, answerLabel);
}
}
public void Setup()
{
do
{
LeftDisplayIndexes.Shuffle();
Thread.Sleep(300);
RightDisplayIndexes.Shuffle();
} while (SomeLinesAreMatched());
}
private bool SomeLinesAreMatched()
{
for (int i = 0; i < LeftDisplayIndexes.Count; i++)
{
int leftIndex = LeftDisplayIndexes[i];
int rightIndex = RightDisplayIndexes[i];
if (leftIndex == rightIndex)
return true;
}
return false;
}
public void DisplayAsAnswer(int numberedIndex)
{
Console.WriteLine("");
Console.WriteLine("--ANSWER TO {0}:-------------------------", _numbers[numberedIndex]);
for (int i = 0; i < Collection.Count; i++)
{
int leftIndex = LeftDisplayIndexes[i];
int rightIndex = RightDisplayIndexes[i];
Console.WriteLine("{0}. {1,-12}{2}. {3}", _numbers[i], Collection[leftIndex].LeftText, _letters[i], Collection[rightIndex].RightText);
}
}
}
public class MatchingItem
{
public string LeftText { get; set; }
public string RightText { get; set; }
public MatchingItem(string leftText, string rightText)
{
LeftText = leftText;
RightText = rightText;
}
}
public static class Helpers
{
public static void Shuffle<T>(this IList<T> list)
{
Random rng = new Random();
int n = list.Count;
while (n > 1)
{
n--;
int k = rng.Next(n + 1);
T value = list[k];
list[k] = list[n];
list[n] = value;
}
}
}
}
【问题讨论】：
-
你应该在谷歌上搜索“随机”，你会惊讶于这是多么困难，并且很难实施......（甚至，关于什么是“真正随机”的协议很少意思）
-
@Charles：我认为他的问题的答案更为基本。他的意思不是数学意义上的“真正随机”，只是“这两列不应该以相同的方式排序”=P.
-
Random minutes in C# 2.0 的可能重复项
-
@Claudiu，是的，我看你是对的.. 他的问题只是对 Random 类的误解/滥用..