Grundy.cs

using System;
using System.Collections.Generic;
using System.Linq;
public class Hello{
    public static void Main(){
        // Your code here!
        var N = int.Parse(Console.ReadLine());
        var array = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        CountUp game = new CountUp(N, array);
        game.Solve();
        Array.Reverse(game.Grundy);
        Console.WriteLine(string.Join(",",game.Grundy));
    }
}
public class CountUp{
    public CountUp(int goal, int[] array){
        this.goal = goal;
        this.nums = array;
        grundy = new int[goal+1];
    }
    int[] grundy;
    public int[] Grundy{
        get{
            return grundy;
        }
    }
    int[] nums;
    int goal;
    public void Solve(){
        CalcGrundy(0);
    }
    int CalcGrundy(int n){
        int max = 0;
        HashSet<int> g = new HashSet<int>();
        foreach(int num in nums){
            int tmp = n + num;
            if(tmp > goal) continue;
            else if(tmp == goal){
                g.Add(0);
            }
            else{
                if(grundy[tmp] == default(int)){
                    g.Add(CalcGrundy(tmp));
                }
                else{
                    g.Add(grundy[tmp]);
                }
            }
        }
        for(int i=0;;i++){
            if(!g.Contains(i)){
                grundy[n] = i;
                return i;
            }
        }
    } 
}