第2回PAST H 1-9 Grid

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 4");
            WillReturn.Add("1S23");
            WillReturn.Add("4567");
            WillReturn.Add("89G1");
            //17
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("1 11");
            WillReturn.Add("S134258976G");
            //20
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("3 3");
            WillReturn.Add("S12");
            WillReturn.Add("4G7");
            WillReturn.Add("593");
            //-1
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

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

    struct JyoutaiDef
    {
        internal int CurrNum;
        internal int CurrX;
        internal int CurrY;
        internal int SumCost;
    }

    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);

        // Sを0、Gを10として、座標のList[数値]なDict
        var NumPosListDict = new Dictionary<int, List<PointDef>>();

        for (int LoopX = 0; LoopX <= UB_X; LoopX++) {
            for (int LoopY = 0; LoopY <= UB_Y; LoopY++) {
                int CurrNum;
                if (BanArr[LoopX, LoopY] == 'S') CurrNum = 0;
                else if (BanArr[LoopX, LoopY] == 'G') CurrNum = 10;
                else CurrNum = BanArr[LoopX, LoopY] - '0';

                if (NumPosListDict.ContainsKey(CurrNum) == false) {
                    NumPosListDict[CurrNum] = new List<PointDef>();
                }
                NumPosListDict[CurrNum].Add(new PointDef() { X = LoopX, Y = LoopY });
            }
        }

        int StaX = NumPosListDict[0][0].X;
        int StaY = NumPosListDict[0][0].Y;
        int GoalX = NumPosListDict[10][0].X;
        int GoalY = NumPosListDict[10][0].Y;

        var Stk = new Stack<JyoutaiDef>();
        JyoutaiDef WillPush;
        WillPush.CurrNum = 0;
        WillPush.CurrX = StaX;
        WillPush.CurrY = StaY;
        WillPush.SumCost = 0;
        Stk.Push(WillPush);

        // 最小コスト[現在座標のハッシュ値]なDict
        var MinCostDict = new Dictionary<int, int>();
        MinCostDict[GetHash(StaX, StaY)] = 0;

        bool FoundAnswer = false;
        int Answer = int.MaxValue;
        while (Stk.Count > 0) {
            JyoutaiDef Popped = Stk.Pop();

            // クリア判定
            if (Popped.CurrNum == 10) {
                FoundAnswer = true;
                Answer = Popped.SumCost;
                continue;
            }

            int NextNum = Popped.CurrNum + 1;
            if (NumPosListDict.ContainsKey(NextNum) == false) {
                continue;
            }
            foreach (PointDef EachNextPoint in NumPosListDict[NextNum]) {
                WillPush.CurrNum = NextNum;
                WillPush.CurrX = EachNextPoint.X;
                WillPush.CurrY = EachNextPoint.Y;

                int Manhattan = DeriveManhattan(Popped.CurrX, Popped.CurrY,
                                                WillPush.CurrX, WillPush.CurrY);

                WillPush.SumCost = Popped.SumCost + Manhattan;

                int Hash = GetHash(WillPush.CurrX, WillPush.CurrY);
                if (MinCostDict.ContainsKey(Hash)) {
                    if (MinCostDict[Hash] <= WillPush.SumCost) {
                        continue;
                    }
                }
                MinCostDict[Hash] = WillPush.SumCost;
                Stk.Push(WillPush);
            }
        }

        if (FoundAnswer) Console.WriteLine(Answer);
        else Console.WriteLine(-1);
    }

    // 座標のハッシュ値を返す
    static int GetHash(int pX, int pY)
    {
        return pX * 100 + pY;
    }

    // 2つの座標のマンハッタン距離を返す
    static int DeriveManhattan(int pX1, int pY1, int pX2, int pY2)
    {
        int WillReturn = 0;
        WillReturn += Math.Abs(pX1 - pX2);
        WillReturn += Math.Abs(pY1 - pY2);
        return WillReturn;
    }

    ////////////////////////////////////////////////////////////////
    // 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

DFSで解いてます。