結果

問題 No.3060 Erase Binary Matrix
ユーザー 紙ぺーぱー
提出日時 2025-03-31 13:53:09
言語 C#(csc)
(csc 3.9.0)
結果
WA  
実行時間 -
コード長 5,790 bytes
コンパイル時間 1,474 ms
コンパイル使用メモリ 120,660 KB
実行使用メモリ 29,484 KB
最終ジャッジ日時 2025-03-31 13:53:15
合計ジャッジ時間 5,931 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample WA * 1 RE * 1
other WA * 12 RE * 37
権限があれば一括ダウンロードができます
コンパイルメッセージ
Microsoft (R) Visual C# Compiler version 3.9.0-6.21124.20 (db94f4cc)
Copyright (C) Microsoft Corporation. All rights reserved.

ソースコード

diff # 

using System;
using System.Linq;
using System.Collections.Generic;
using Debug = System.Diagnostics.Trace;
using SB = System.Text.StringBuilder;
using static System.Math;
using static Program.IO.Scanner;
using Number = System.Int64;
using System.Numerics;
using C = System.Int64;
using V = System.Int64;
using System.ComponentModel;

#region IO
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)) { }
    }
    static public class Scanner
    {
        public static StreamScanner sc = new StreamScanner(Console.OpenStandardInput());
        public static int ri => sc.Integer();
        public static long rl => sc.Long();
        public static string rs => sc.Scan();
        public static double rd => sc.Double();
    }
    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 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 = true });
        var solver = new Program.Solver();
        //*
        var t = new System.Threading.Thread(solver.Solve, 50000000);
        t.Start();
        t.Join();
        //*/
        // solver.Solve();
        Console.Out.Flush();
    }
}
#endregion

namespace Program
{
    public class Solver
    {

        public void Solve()
        {
          var n=ri;
          var m=ri;
          if(m%2!=0){
            Console.WriteLine(-1);
            return;
          }
          var f=new int[m];
          var t=new int[m];
          var cnt=Enumerate(n, x => new List<int>());
          for (int i = 0; i < m; i++){
            f[i]=ri-1;
            t[i]=ri-1;
            if(f[i]==0&&t[i]==n-1){
                Console.WriteLine(-1);
                return;
            }
            cnt[f[i]].Add(i);
            cnt[t[i]].Add(i);
          }
          var ans=new char[m];
          if(Max(cnt[0].Count,cnt[n-1].Count)*2>m){
            for (int i = 0; i < m; i++){
                ans[i]='R';
            }
            if(cnt[0].Count*2>m){
                foreach(var x in cnt[0].OrderBy(x=>-cnt[t[x]].Count).Take(m/2)){
                    ans[x]='B';
                }
            }else{
                    foreach(var x in cnt[n-1].OrderBy(x=>-cnt[f[x]].Count).Take(m/2)){
                    ans[x]='B';
                }

            }

          }else{
            var used=new bool[m];
            int r=0;int b=0;
            foreach(var x in cnt[0]){ans[x]='R';used[x]=true;r++;}
            foreach(var x in cnt[n-1]){ans[x]='B';used[x]=true;b++;}
           
            for (int i = 0; i < m; i++)if(!used[i]){
                if(r>b){ans[i]='B';b++;}
                else {ans[i]='R';r++;}
            }
          }
          Console.WriteLine(ans.AsString());
          

        }
        const long INF = 1L << 60;
        static int[] dx = { -1, 0, 1, 0 };
        static int[] dy = { 0, 1, 0, -1 };
        /*
        static IEnumerable<int> rep(int n) { for (int i = 0; i < n; i++) yield return i; }
        static IEnumerable<(int, int)> rep(int n, int m)
        {
            for (int i = 0; i < n; i++)
                for (int j = 0; j < m; j++) yield return (i, j);
        }
        */
        static T[] Enumerate<T>(int n, Func<int, T> f)
        {
            var a = new T[n]; for (int i = 0; i < a.Length; ++i) a[i] = f(i); return a;
        }
        static T[][] Enumerate<T>(int n, int m, Func<int, int, T> f)
        {
            return Enumerate(n, x => Enumerate(m, y => f(x, y)));
        }
        static T[][][] Enumerate<T>(int n, int m, int k, Func<int, int, int, T> f)
        {
            return Enumerate(n, x => Enumerate(m, k, (y, z) => f(x, y, z)));
        }
        static public void Swap<T>(ref T a, ref T b) { var tmp = a; a = b; b = tmp; }
    }
}
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