猜数字的算法的一个简单实现

猜数字的算法的一个简单实现，用的最简单的算法，权当编程练习。

1 class GuessNumber
2 {
3 public static IEnumerable<int> Guess(Func<int, int> testHanlder)
4 {
5 var validNumers = Enumerable.Range(1, 9); //有效数字范围为1-9
6 var candicateNum = from n1 in validNumers
7 from n2 in validNumers
8 from n3 in validNumers
9 from n4 in validNumers
10 where new int[] { n1, n2, n3, n4 }.Distinct().Count() == 4 //过滤掉有重复的数字
11 select n1 * 1000 + n2 * 100 + n3 * 10 + n4;
12
13 while (true)
14 {
15 var num = candicateNum.First();
16 yield return num;
17
18 var result = testHanlder(num);
19 if (result == 40)
20 yield break;
21
22 candicateNum = candicateNum.Where(i => Test(i, num) == result);
23 }
24 }
25
26 public static IEnumerable<int> Guess(int num)
27 {
28 return Guess(i => Test(i, num));
29 }
30
31 //为了简单返回值为int型，如2A1B则返回21
32 public static int Test(int num1, int num2)
33 {
34 var value1 = num1.ToString("0000");
35 var value2 = num2.ToString("0000");
36
37 Contract.Assume((value1.Length == 4) && (value2.Length == 4));
38
39 var query = value1.Zip(value2, (ch1, ch2) => new
40 {
41 MatchA = (ch1 == ch2),
42 MatchB = (ch1 != ch2) && (value1.Contains(ch2))
43 }).ToArray();
44
45 var aCount = query.Count(i => i.MatchA);
46 var bCount = query.Count(i => i.MatchB);
47
48 return aCount * 10 + bCount;
49 }
50 }