Submission #187767

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Source Code Expand

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ABC0011
{
    public class D
    {
        public static void Main()
        {
            string[] line;
            line = Console.ReadLine().Trim().Split();
            long N = long.Parse(line[0]);
            long D = long.Parse(line[1]);
            line = Console.ReadLine().Trim().Split();
            long X = long.Parse(line[0]);
            long Y = long.Parse(line[1]);

            System.Diagnostics.Trace.Assert(N <= 30);

            int d = 50;
            int MAX_X = 101;
            int MAX_Y = 101;
            var p = new double[51, MAX_X, MAX_Y];
            p[0, d, d] = 1;
            for (int i = 0; i < N; ++i)
            {
                for (int x = 0; x < MAX_X; ++x)
                {
                    for (int y = 0; y < MAX_Y; ++y)
                    {
                        double cur = p[i, x, y];
                        if (x + 1 < MAX_X) p[i + 1, x + 1, y] += cur / 4;
                        if (x > 0) p[i + 1, x - 1, y] += cur / 4;
                        if (y + 1 < MAX_Y) p[i + 1, x, y + 1] += cur / 4;
                        if (y > 0) p[i + 1, x, y - 1] += cur / 4;
                    }
                }
            }

            double res = 0;
            for (int x = 0; x < MAX_X; ++x)
            {
                for (int y = 0; y < MAX_Y; ++y)
                {
                    int dx = x - d;
                    int dy = y - d;
                    if (D * dx == X && D * dy == Y) { res = p[N, x, y]; }
                }
            }
            Console.WriteLine(res.ToString("f12"));
        }
    }
}

Submission Info

Judge Result