ABC184-E Third Avenue

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("S.b.b");
            WillReturn.Add("a.a.G");
            //4
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("11 11");
            WillReturn.Add("S##...#c...");
            WillReturn.Add("...#d.#.#..");
            WillReturn.Add("..........#");
            WillReturn.Add(".#....#...#");
            WillReturn.Add("#.....bc...");
            WillReturn.Add("#.##......#");
            WillReturn.Add(".......c..#");
            WillReturn.Add("..#........");
            WillReturn.Add("a..........");
            WillReturn.Add("d..#...a...");
            WillReturn.Add(".#........G");
            //14
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("11 11");
            WillReturn.Add(".#.#.e#a...");
            WillReturn.Add(".b..##..#..");
            WillReturn.Add("#....#.#..#");
            WillReturn.Add(".#dd..#..#.");
            WillReturn.Add("....#...#e.");
            WillReturn.Add("c#.#a....#.");
            WillReturn.Add(".....#..#.e");
            WillReturn.Add(".#....#b.#.");
            WillReturn.Add(".#...#..#..");
            WillReturn.Add("......#c#G.");
            WillReturn.Add("#..S...#...");
            //-1
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    struct JyoutaiDef
    {
        internal int CurrX;
        internal int CurrY;
        internal int Level;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        char[,] BanArr = CreateBanArr(InputList.Skip(1));
        int UB_X = BanArr.GetUpperBound(0);
        int UB_Y = BanArr.GetUpperBound(1);

        int StaX = -1, StaY = -1;
        for (int X = 0; X <= UB_X; X++) {
            for (int Y = 0; Y <= UB_Y; Y++) {
                if (BanArr[X, Y] == 'S') {
                    StaX = X; StaY = Y;
                }
            }
        }

        // ワープできる座標のList[文字]なDict
        var WarpListDict = new Dictionary<char, List<PointDef>>();
        for (int X = 0; X <= UB_X; X++) {
            for (int Y = 0; Y <= UB_Y; Y++) {
                char CurrChar = BanArr[X, Y];
                if ('a' <= CurrChar && CurrChar <= 'z') {
                    if (WarpListDict.ContainsKey(CurrChar) == false) {
                        WarpListDict[CurrChar] = new List<PointDef>();
                    }
                    PointDef WillAdd;
                    WillAdd.X = X;
                    WillAdd.Y = Y;
                    WarpListDict[CurrChar].Add(WillAdd);
                }
            }
        }

        var Que = new Queue<JyoutaiDef>();
        JyoutaiDef WillEnque;
        WillEnque.CurrX = StaX;
        WillEnque.CurrY = StaY;
        WillEnque.Level = 0;
        Que.Enqueue(WillEnque);

        var VisitedSet = new HashSet<int>();
        VisitedSet.Add(GetHash(StaX, StaY));

        bool FoundAnswer = false;
        int Answer = int.MaxValue;
        while (Que.Count > 0) {
            JyoutaiDef Dequeued = Que.Dequeue();

            // クリア判定
            if (BanArr[Dequeued.CurrX, Dequeued.CurrY] == 'G') {
                FoundAnswer = true;
                Answer = Math.Min(Answer, Dequeued.Level);
            }

            // 枝切り
            if (FoundAnswer && Dequeued.Level >= Answer)
                continue;

            Action<int, int> EnqueueAct = (pNewX, pNewY) =>
            {
                if (pNewX < 0 || UB_X < pNewX) return;
                if (pNewY < 0 || UB_Y < pNewY) return;

                if (BanArr[pNewX, pNewY] == '#') return;

                int Hash = GetHash(pNewX, pNewY);
                if (VisitedSet.Add(Hash)) {
                    WillEnque.CurrX = pNewX;
                    WillEnque.CurrY = pNewY;
                    WillEnque.Level = Dequeued.Level + 1;
                    Que.Enqueue(WillEnque);
                }
            };

            char CurrChar = BanArr[Dequeued.CurrX, Dequeued.CurrY];

            // テレポート移動
            if (WarpListDict.ContainsKey(CurrChar)) {
                foreach (PointDef EachPoint in WarpListDict[CurrChar]) {
                    EnqueueAct(EachPoint.X, EachPoint.Y);
                }
            }
            // Removeしておく
            WarpListDict.Remove(CurrChar);

            // 徒歩移動
            EnqueueAct(Dequeued.CurrX, Dequeued.CurrY - 1);
            EnqueueAct(Dequeued.CurrX, Dequeued.CurrY + 1);
            EnqueueAct(Dequeued.CurrX - 1, Dequeued.CurrY);
            EnqueueAct(Dequeued.CurrX + 1, Dequeued.CurrY);
        }
        if (FoundAnswer) {
            Console.WriteLine(Answer);
        }
        else {
            Console.WriteLine(-1);
        }
    }

    struct PointDef
    {
        internal int X;
        internal int Y;
    }

    static int GetHash(int pX, int pY)
    {
        return pX * 10000 + pY;
    }

    ////////////////////////////////////////////////////////////////
    // IEnumerable<string>をcharの2次元配列に設定する
    ////////////////////////////////////////////////////////////////
    static char[,] CreateBanArr(IEnumerable<string> pStrEnum)
    {
        var StrList = pStrEnum.ToList();
        if (StrList.Count == 0) {
            return new char[0, 0];
        }
        int UB_X = StrList[0].Length - 1;
        int UB_Y = StrList.Count - 1;

        char[,] WillReturn = new char[UB_X + 1, UB_Y + 1];

        for (int Y = 0; Y <= UB_Y; Y++) {
            for (int X = 0; X <= UB_X; X++) {
                WillReturn[X, Y] = StrList[Y][X];
            }
        }
        return WillReturn;
    }
}

解説

幅優先探索で
一度使用したテレポートはRemoveするようにしてます。