AOJ 0558 チーズ (Cheese)

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 3 1");
            WillReturn.Add("S..");
            WillReturn.Add("...");
            WillReturn.Add("..1");
            //4
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4 5 2");
            WillReturn.Add(".X..1");
            WillReturn.Add("....X");
            WillReturn.Add(".XX.S");
            WillReturn.Add(".2.X.");
            //12
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("10 10 9");
            WillReturn.Add(".X...X.S.X");
            WillReturn.Add("6..5X..X1X");
            WillReturn.Add("...XXXX..X");
            WillReturn.Add("X..9X...X.");
            WillReturn.Add("8.X2X..X3X");
            WillReturn.Add("...XX.X4..");
            WillReturn.Add("XX....7X..");
            WillReturn.Add("X..X..XX..");
            WillReturn.Add("X...X.XX..");
            WillReturn.Add("..X.......");
            //91
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

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

    static char[,] mBanArr;
    static int UB_X;
    static int UB_Y;

    static void Main()
    {
        List<string> InputList = GetInputList();
        mBanArr = CreateBanArr(InputList.Skip(1));
        UB_X = mBanArr.GetUpperBound(0);
        UB_Y = mBanArr.GetUpperBound(1);

        var PointPosDict = new SortedDictionary<char, PointDef>();
        for (int LoopX = 0; LoopX <= UB_X; LoopX++) {
            for (int LoopY = 0; LoopY <= UB_Y; LoopY++) {
                char CurrChar = mBanArr[LoopX, LoopY];
                if (CurrChar == 'S') {
                    CurrChar = '0';
                }
                if ('0' <= CurrChar && CurrChar <= '9') {
                    PointDef CurrPos;
                    CurrPos.X = LoopX;
                    CurrPos.Y = LoopY;
                    PointPosDict[CurrChar] = CurrPos;
                }
            }
        }

        char[] KeysArr = PointPosDict.Keys.ToArray();
        int UB = KeysArr.GetUpperBound(0);
        long Answer = 0;
        for (int I = 0; I <= UB - 1; I++) {
            PointDef StaPos = PointPosDict[KeysArr[I]];
            PointDef EndPos = PointPosDict[KeysArr[I + 1]];
            Answer += ExecBFS(StaPos, EndPos);
        }
        Console.WriteLine(Answer);
    }

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

    // スタート座標とゴール座標を引数として、BFSで最短距離を求めて返す
    static int ExecBFS(PointDef pStaPos, PointDef pGoalPos)
    {
        var Que = new Queue<JyoutaiDef>();
        JyoutaiDef WillEnque;
        WillEnque.CurrX = pStaPos.X;
        WillEnque.CurrY = pStaPos.Y;
        WillEnque.Level = 0;
        Que.Enqueue(WillEnque);

        var VisitedSet = new HashSet<int>();
        VisitedSet.Add(GetHash(pStaPos.X, pStaPos.Y));

        while (Que.Count > 0) {
            JyoutaiDef Dequeued = Que.Dequeue();

            // クリア判定
            if (Dequeued.CurrX == pGoalPos.X && Dequeued.CurrY == pGoalPos.Y) {
                return Dequeued.Level;
            }

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

                if (mBanArr[pNewX, pNewY] == 'X') return;

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

                    Que.Enqueue(WillEnque);
                }
            };

            EnqueAct(Dequeued.CurrX, Dequeued.CurrY - 1);
            EnqueAct(Dequeued.CurrX, Dequeued.CurrY + 1);
            EnqueAct(Dequeued.CurrX - 1, Dequeued.CurrY);
            EnqueAct(Dequeued.CurrX + 1, Dequeued.CurrY);
        }
        return -1;
    }

    static int GetHash(int pX, int pY)
    {
        return 1000 * pX + 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

スタートとゴールの組み合わせごとに、BFSで最短距離を求めてます。