提出 #36416984

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ソースコード 拡げる

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

namespace Tasks
{
    public class C
    {
        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>();
            var G = new Dictionary<int, List<int>>();
            for (var i = 0; i < N; i++)
            {
                var (a, b) = Scanner.Scan<int, int>();
                if (!G.ContainsKey(a)) G[a] = new List<int>();
                if (!G.ContainsKey(b)) G[b] = new List<int>();
                G[a].Add(b);
                G[b].Add(a);
            }

            var used = new HashSet<int> { 1 };
            var queue = new Queue<int>();
            queue.Enqueue(1);
            while (queue.Count > 0)
            {
                var u = queue.Dequeue();
                if (!G.ContainsKey(u)) continue;
                foreach (var v in G[u])
                {
                    if (used.Contains(v)) continue;
                    used.Add(v);
                    queue.Enqueue(v);
                }
            }

            var answer = used.Max();
            Console.WriteLine(answer);
        }

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

提出情報

ジャッジ結果