ABC470-C Inc, Dec, Xor

問題へのリンク

C#のソース

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

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("2 5");
            WillReturn.Add("1 2");
            WillReturn.Add("1 2");
            WillReturn.Add("1 1");
            WillReturn.Add("2");
            WillReturn.Add("2");
            //1
            //2
            //3
            //1
            //0
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("3 8");
            WillReturn.Add("1 2");
            WillReturn.Add("1 3");
            WillReturn.Add("1 1");
            WillReturn.Add("1 2");
            WillReturn.Add("1 1");
            WillReturn.Add("2");
            WillReturn.Add("1 3");
            WillReturn.Add("1 1");
            //1
            //0
            //1
            //2
            //1
            //0
            //1
            //2
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static long[] GetSplitArr(string pStr)
    {
        return (pStr == "" ? new string[0] : pStr.Split(' ')).Select(pX => long.Parse(pX)).ToArray();
    }

    static void Main()
    {
        List<string> InputList = GetInputList();

        long[] wkArr = { };
        Action<string> SplitAct = (pStr) => wkArr = GetSplitArr(pStr);

        // 値[添字]なDict
        var ValDict = new Dictionary<long, long>();

        long Answer = 0;
        var sb = new System.Text.StringBuilder();
        foreach (string EachStr in InputList.Skip(1)) {
            SplitAct(EachStr);
            long Type = wkArr[0];
            if (Type == 1) {
                long Target = wkArr[1];
                if (ValDict.ContainsKey(Target)) {
                    Answer ^= ValDict[Target];
                }
                else {
                    ValDict[Target] = 0;
                }
                ValDict[Target]++;
                Answer ^= ValDict[Target];
            }
            if (Type == 2) {
                var WillRemoveList = new List<long>();
                foreach (long EachKey in ValDict.Keys.ToArray()) {
                    Answer ^= ValDict[EachKey];
                    ValDict[EachKey]--;
                    if (ValDict[EachKey] == 0) {
                        WillRemoveList.Add(EachKey);
                    }
                    else {
                        Answer ^= ValDict[EachKey];
                    }
                }
                WillRemoveList.ForEach(pX => ValDict.Remove(pX));
            }
            sb.Append(Answer);
            sb.AppendLine();
        }
        Console.Write(sb.ToString());
    }
}

解説

XORの世界では、足し算と引き算は、同じことをふまえて、
値[添字]なDictを用意して、解を差分更新してます。