Submission #2156855

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Source Code Expand

using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Debug;
using SB = System.Text.StringBuilder;
using Number = System.Int64;
using System.Numerics;
using static System.Math;
namespace Program {
    public class Solver {
        Random rnd = new Random(0);
        public void Solve() {
            var n = 6;
            var P = Enumerate(n, x => ri / 100.0);
            var Q = Enumerate(n, x => ri / 100.0);
            //Petr はある確率 p で P を選ぶ．
            //touristがそれを知っているときに最適に動く
            //Petr はどういう p を選ぶのが最適か？
            Func<double, double> f = p =>
            {
                var res = 0.0;
                for (int i = 0; i < 6; i++)
                {
                    var pp = p * P[i] + (1 - p) * Q[i];
                    res += Math.Max(p * P[i], (1 - p) * Q[i]);
                }
                return res;
            };
            var ans = Algorithm.GoldenSectionSearch(0.0, 1.0, f);
            Console.WriteLine("{0:0.0000000000000}", ans);
        }
        const long INF = 1L << 60;
        static int[] dx = { -1, 0, 1, 0 };
        static int[] dy = { 0, 1, 0, -1 };

        int ri { get { return sc.Integer(); } }
        long rl { get { return sc.Long(); } }
        double rd { get { return sc.Double(); } }
        string rs { get { return sc.Scan(); } }
        public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput());

        static T[] Enumerate<T>(int n, Func<int, T> f) {
            var a = new T[n];
            for (int i = 0; i < n; ++i) a[i] = f(i);
            return a;
        }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}

#region main
static class Ex {
    static public string AsString(this IEnumerable<char> ie) { return new string(ie.ToArray()); }

    static public string AsJoinedString<T>(this IEnumerable<T> ie, string st = " ") {
        return string.Join(st, ie);
    }

    static public void Main() {
        Console.SetOut(new Program.IO.Printer(Console.OpenStandardOutput()) { AutoFlush = false });
        var solver = new Program.Solver();
        try
        {
            solver.Solve();
            Console.Out.Flush();
        }
        catch { }
    }
}
#endregion
#region Ex
namespace Program.IO {
    using System.IO;
    using System.Text;
    using System.Globalization;

    public class Printer: StreamWriter {
        public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
        public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { }
    }

    public class StreamScanner {
        public StreamScanner(Stream stream) { str = stream; }

        public readonly Stream str;
        private readonly byte[] buf = new byte[1024];
        private int len, ptr;
        public bool isEof = false;
        public bool IsEndOfStream { get { return isEof; } }

        private byte read() {
            if (isEof) return 0;
            if (ptr >= len)
            {
                ptr = 0;
                if ((len = str.Read(buf, 0, 1024)) <= 0)
                {
                    isEof = true;
                    return 0;
                }
            }
            return buf[ptr++];
        }

        public char Char() {
            byte b = 0;
            do b = read(); while ((b < 33 || 126 < b) && !isEof);
            return (char)b;
        }
        public string Scan() {
            var sb = new StringBuilder();
            for (var b = Char(); b >= 33 && b <= 126; b = (char)read()) sb.Append(b);
            return sb.ToString();
        }
        public string ScanLine() {
            var sb = new StringBuilder();
            for (var b = Char(); b != '\n' && b != 0; b = (char)read()) if (b != '\r') sb.Append(b);
            return sb.ToString();
        }
        public long Long() { return isEof ? long.MinValue : long.Parse(Scan()); }
        public int Integer() { return isEof ? int.MinValue : int.Parse(Scan()); }
        public double Double() { return isEof ? double.NaN : double.Parse(Scan(), CultureInfo.InvariantCulture); }
    }
}

#endregion
#region GoldenSectionSearch
static public partial class Algorithm {
    static public double GoldenSectionSearch(double a, double b, Func<double, double> function) {
        var r = 2 / (3 + Math.Sqrt(5));
        var c = a + r * (b - a);
        var d = b - r * (b - a);
        var fc = function(c);
        var fd = function(d);
        for (int i = 0; i < 100; i++)
        {
            //if (fc < fd)//凸
            if (fc > fd)//凹
            {
                a = c; c = d; d = b - r * (b - a);
                fc = fd; fd = function(d);
            }
            else
            {
                b = d; d = c; c = a + r * (b - a);
                fd = fc; fc = function(c);
            }
        }
        return fc;
    }
}
#endregion

Submission Info

Judge Result