Submission #40840107

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Source Code Expand

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Numerics;

namespace Tasks
{
    public class D
    {
        public static void Main()
        {
            // using var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            // Console.SetOut(sw);
            Solve();
            // Console.Out.Flush();
        }

        public static void Solve()
        {
            var N = Scanner.Scan<int>();

            bool F(int x)
            {
                Console.WriteLine($"?{x + 1}");
                var v = Scanner.Scan<int>();
                return v == 1;
            }

            var answer = BinarySearch(0, N, F);
            Console.WriteLine($"!{answer}");
        }

        public static int BinarySearch(int ng, int ok, Func<int, bool> func)
        {
            while (Math.Abs(ok - ng) > 1)
            {
                var m = (ok + ng) / 2;
                if (func(m)) ok = m;
                else ng = m;
            }
            return ok;
        }

        public static class Scanner
        {
            public static T Scan<T>() where T : IConvertible => Convert<T>(Scan()[0]);
            public static (T1, T2) Scan<T1, T2>() where T1 : IConvertible where T2 : IConvertible
            {
                var buffer = Scan();
                return (Convert<T1>(buffer[0]), Convert<T2>(buffer[1]));
            }
            public static (T1, T2, T3) Scan<T1, T2, T3>() where T1 : IConvertible where T2 : IConvertible where T3 : IConvertible
            {
                var buffer = Scan();
                return (Convert<T1>(buffer[0]), Convert<T2>(buffer[1]), Convert<T3>(buffer[2]));
            }
            public static (T1, T2, T3, T4) Scan<T1, T2, T3, T4>() where T1 : IConvertible where T2 : IConvertible where T3 : IConvertible where T4 : IConvertible
            {
                var buffer = Scan();
                return (Convert<T1>(buffer[0]), Convert<T2>(buffer[1]), Convert<T3>(buffer[2]), Convert<T4>(buffer[3]));
            }
            public static (T1, T2, T3, T4, T5) Scan<T1, T2, T3, T4, T5>() where T1 : IConvertible where T2 : IConvertible where T3 : IConvertible where T4 : IConvertible where T5 : IConvertible
            {
                var buffer = Scan();
                return (Convert<T1>(buffer[0]), Convert<T2>(buffer[1]), Convert<T3>(buffer[2]), Convert<T4>(buffer[3]), Convert<T5>(buffer[4]));
            }
            public static (T1, T2, T3, T4, T5, T6) Scan<T1, T2, T3, T4, T5, T6>() where T1 : IConvertible where T2 : IConvertible where T3 : IConvertible where T4 : IConvertible where T5 : IConvertible where T6 : IConvertible
            {
                var buffer = Scan();
                return (Convert<T1>(buffer[0]), Convert<T2>(buffer[1]), Convert<T3>(buffer[2]), Convert<T4>(buffer[3]), Convert<T5>(buffer[4]), Convert<T6>(buffer[5]));
            }
            public static IEnumerable<T> ScanEnumerable<T>() where T : IConvertible => Scan().Select(Convert<T>);
            private static string[] Scan()
            {
                var line = Console.ReadLine()?.Trim() ?? string.Empty;
                return string.IsNullOrEmpty(line) ? Array.Empty<string>() : line.Split(' ');
            }
            private static T Convert<T>(string value) where T : IConvertible => (T)System.Convert.ChangeType(value, typeof(T));
        }
    }
}

Submission Info

Judge Result