ABC390-D Stone 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("3");
            WillReturn.Add("2 5 7");
            //3
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2");
            WillReturn.Add("100000000000000000 100000000000000000");
            //2
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("6");
            WillReturn.Add("71 74 45 34 31 60");
            //84
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        long[] AArr = InputList[1].Split(' ').Select(pX => long.Parse(pX)).ToArray();
        int UB = AArr.GetUpperBound(0);

        var Stk = new Stack<JyoutaiDef>();
        JyoutaiDef WillPush;
        WillPush.ValList = new List<long>();
        WillPush.CurrInd = 0;
        Stk.Push(WillPush);

        var AnswerList = new List<long>();
        while (Stk.Count > 0) {
            JyoutaiDef Popped = Stk.Pop();
            int CurrInd = Popped.CurrInd;

            if (CurrInd > UB) {
                long XOR = 0;
                Popped.ValList.ForEach(pX => XOR ^= pX);
                AnswerList.Add(XOR);
                continue;
            }

            // Listの要素に足し算する場合
            for (int I = 0; I <= Popped.ValList.Count - 1; I++) {
                WillPush.ValList = new List<long>(Popped.ValList);
                WillPush.ValList[I] = Popped.ValList[I] + AArr[CurrInd];
                WillPush.CurrInd = CurrInd + 1;
                Stk.Push(WillPush);
            }

            // ListにAddする場合
            WillPush.ValList = new List<long>(Popped.ValList);
            WillPush.ValList.Add(AArr[CurrInd]);
            WillPush.CurrInd = CurrInd + 1;
            Stk.Push(WillPush);
        }

        // ソートして前と不一致かで、uniq件数を調べる
        long Answer = 0;
        AnswerList.Sort();
        for (int I = 0; I <= AnswerList.Count - 1; I++) {
            if (I == 0) {
                Answer++;
                continue;
            }
            if (AnswerList[I] != AnswerList[I - 1]) {
                Answer++;
            }
        }
        Console.WriteLine(Answer);
    }

    struct JyoutaiDef
    {
        internal List<long> ValList;
        internal int CurrInd;
    }
}

解説

ベル数の12は、
4213597なのでDFSで全探索してます。

重複チェックをHashSetでやるとTLEするので
ソートして前後との差異を見てます。