ABC197-C ORXOR

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("1 5 7");
            //2
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("3");
            WillReturn.Add("10 10 10");
            //0
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("4");
            WillReturn.Add("1 3 3 1");
            //0
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

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

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

        long[] AArr = InputList[1].Split(' ').Select(pX => long.Parse(pX)).ToArray();
        int UB = AArr.GetUpperBound(0);

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

        long Answer = long.MaxValue;
        while (Stk.Count > 0) {
            JyoutaiDef Popped = Stk.Pop();

            if (Popped.CurrInd > UB) {
                long AnswerKouho = Popped.ORList[0];
                for (int I = 1; I <= Popped.ORList.Count - 1; I++) {
                    AnswerKouho ^= Popped.ORList[I];
                }
                Answer = Math.Min(Answer, AnswerKouho);
                continue;
            }

            // 分割しない場合
            if (Popped.ORList.Count > 0) {
                WillPush.CurrInd = Popped.CurrInd + 1;
                WillPush.ORList = new List<long>(Popped.ORList);

                int LastInd = WillPush.ORList.Count - 1;
                long LastVal = WillPush.ORList[LastInd];
                LastVal |= AArr[Popped.CurrInd];

                WillPush.ORList.RemoveAt(LastInd);
                WillPush.ORList.Add(LastVal);
                Stk.Push(WillPush);
            }

            // 分割する場合
            WillPush.CurrInd = Popped.CurrInd + 1;
            WillPush.ORList = new List<long>(Popped.ORList);
            WillPush.ORList.Add(AArr[Popped.CurrInd]);
            Stk.Push(WillPush);
        }
        Console.WriteLine(Answer);
    }
}

解説

制約が緩いので、深さ優先探索で、全ての分割を試してます。

C#での
ビットの論理積(BitAnd)は &
ビットの論理和(BitOr)は |
ビットの排他的論理和は ^
を使います。