using System;
using S = System.String;
using System.Collections.Generic;
partial class M
{
    Dictionary<S, char> d = new Dictionary<S, char>();
    List<S> e = new List<S>();

    int p = 9, m = 999, x, y, z, u, v, i, j, k, h;
    char a = '@', w = '#', f = '.', q = '$', c;
    Random r = new Random();

    M()
    {
        x = y = h = p;

        //Add enemies
        for (i = 0; i < m; i++)
        {
            e.Add(K(r.Next(m) - 499, r.Next(m) - 499));
            d[e[e.Count - 1]] = 'M';
        }

        //set player start
        d[X] = a;

        //get keyboard input
        k = I;
        while (k > 0)
        {
            //save player co-ords
            u = x;
            v = y;

            //handle keyboard return code
            x = k > 2 && k < 20 ? x - 1 : k > 12 ? x + 1 : x;
            y = k % 2 > 0 && k % 10 != 0 ? y - 1 : k % 2 == 0 && k % 10 != 0 ? y + 1 : y;

            //get char at new location
            c = T(X);

            //if player hits an enemy
            if (e.Contains(X))
            {
                //kill the enemy
                e.Remove(X);
                d[X] = f;
            }

            //reset the cursor to top left
            R();

            //win condition met?
            if (c == q) return;

            //if player is somewhere other than floor reset co-ords
            if (c != f)
            {
                x = u;
                y = v;
            }

            //set floor at player's old location and player at new location
            d[K(u, v)] = f;
            d[X] = a;

            //iterate through enemies
            for (z = 0; z < e.Count; z++)
            {
                //store enemy's co-ords
                i = U(e[z], 0);
                j = U(e[z], 1);
                
                //move towards player
                u = i < x ? i + 1 : i > x ? i - 1 : i;
                v = j < y ? j + 1 : j > y ? j - 1 : j;
                
                //get char at new co-ord
                c = T(K(u, v));
                
                //move to new co-ord if it's a floor tile
                if (c == f)
                {
                    e[z] = K(u, v);
                    d[e[z]] = d[K(i, j)];
                    d[K(i, j)] = f;
                }
                
                //if hitting player, deduct player health
                if (c == a) h--;
            }

            //player dead
            if (h < 1) return;

            //calculate viewport size from p
            z = p * 2 - 1;
            
            //draw current state to viewport
            for (j = 0; j < z; j++)
            {
                for (i = 0; i < z; i++)
                {
                    W(T(K(i - p + x, j - p + y)));
                }
                L();
            }
            //draw health
            L(h);
            //get keyboard input
            k = I;
        }
    }

    //converts an x y co-ord to a dictionary key
    S K(int x, int y)
    {
        return S.Format("{0}_{1}", x, y);
    }

    //returns string for most commonly used key
    S X
    {
        get { return K(x, y); }
    }

    //generate a map tile
    char T(S s)
    {
        return d.ContainsKey(s) ? d[s] : d[s] = r.Next(m * p) < 2 ? q : r.Next(9) < 8 ? f : w;
    }

    //converts a key to an x or y co-ord
    int U(S s, int l) { return Int32.Parse((s.Split('_'))[l]); }

    static void Main() { new M(); }
}