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  1. using System;
  2. using System.Collections;
  3. using System.Collections.Generic;
  4. using System.Linq;
  5.  
  6. public class Test
  7. {
  8.     enum Player
  9.     {
  10.         None = -1,
  11.         FirstPlayer = 0,
  12.         SecondPlayer = 1
  13.     };
  14.  
  15.     public static bool CheckWin(int n, IEnumerable<int> coinSequence)
  16.     {
  17.         if (coinSequence == null || coinSequence.Count() != 2 * n)
  18.             throw new ArgumentException("coinSequence size must be equal 2*n");
  19.  
  20.         var forcePlayer = Player.None;
  21.         var currentPlayer = Player.None;
  22.  
  23.         var playerCoins = new int[2] { n, 0 };
  24.         var playerMoved = new int[2] { 0, 0 };
  25.         var coinsOnDesk = 0;
  26.  
  27.         foreach (var coin in coinSequence)
  28.         {
  29.             currentPlayer = (Player)(coin == 1 ? 0 : 1);
  30.  
  31.             // force player
  32.             {
  33.                 if (playerMoved[(int)currentPlayer] > n)
  34.                 {
  35.                     switch (currentPlayer)
  36.                     {
  37.                         case Player.FirstPlayer: forcePlayer = Player.SecondPlayer; break;
  38.                         case Player.SecondPlayer: forcePlayer = Player.FirstPlayer; break;
  39.                         default: throw new Exception("Alg fail"); break;
  40.                     }
  41.                 }
  42.  
  43.                 if (forcePlayer != Player.None)
  44.                     currentPlayer = forcePlayer;
  45.             }
  46.  
  47.             switch (currentPlayer)
  48.             {
  49.                 case Player.FirstPlayer:
  50.                     if (playerCoins[0] != 0)
  51.                     {
  52.                         playerCoins[0]--;
  53.                         coinsOnDesk++;
  54.                     }
  55.                     break;
  56.                 case Player.SecondPlayer:
  57.                     if (coinsOnDesk != 0)
  58.                     {
  59.                         coinsOnDesk--;
  60.                         playerCoins[1]++;
  61.                     }
  62.                     break;
  63.                 default: throw new Exception("Alg fail"); break;
  64.             }
  65.  
  66.             playerMoved[(int)currentPlayer]++;
  67.         }
  68.  
  69.         return (playerCoins[1] == n);
  70.     }
  71.  
  72.     public static IEnumerable<IEnumerable<int>> GenerateCoins(int n)
  73.     {
  74.         if (n == 1)
  75.         {
  76.             yield return new int[] { 1 };
  77.             yield return new int[] { 2 };
  78.             yield break;
  79.         }
  80.  
  81.         var smallerVariants = GenerateCoins(n - 1);
  82.         foreach (var smallerVariant in smallerVariants)
  83.         {
  84.             yield return smallerVariant.Concat(new int[] { 1 });
  85.             yield return smallerVariant.Concat(new int[] { 2 });
  86.         }
  87.  
  88.         yield break;
  89.     }
  90.  
  91.     public static int CountWinsSequences(int n)
  92.     {
  93.         return GenerateCoins(2 * n).Count(coinSequence => CheckWin(n, coinSequence));
  94.     }
  95.  
  96.     public static void Main()
  97.     {
  98.         for (int n = 1; n <= 5; n++)
  99.         {
  100.             Console.WriteLine("n = {0}, wins = {1}", n, CountWinsSequences(n));
  101.         }
  102.     }
  103. }
Success #stdin #stdout 0.05s 34192KB
comments (?)
stdin
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Standard input is empty
stdout
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n = 1, wins = 1
n = 2, wins = 2
n = 3, wins = 5
n = 4, wins = 14
n = 5, wins = 42
https://ideone.com/1Oeqji
language:
C# (gmcs 5.20.1)
created:
11 years ago
visibility:
public

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