ABC413-G Big Banned 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("4 5 5");
            WillReturn.Add("1 4");
            WillReturn.Add("2 3");
            WillReturn.Add("3 2");
            WillReturn.Add("3 4");
            WillReturn.Add("4 2");
            //No
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2 7 3");
            WillReturn.Add("1 2");
            WillReturn.Add("2 4");
            WillReturn.Add("1 6");
            //Yes
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("1 1 0");
            //Yes
        }
        else if (InputPattern == "Input4") {
            WillReturn.Add("10 12 20");
            WillReturn.Add("8 3");
            WillReturn.Add("1 11");
            WillReturn.Add("6 4");
            WillReturn.Add("3 7");
            WillReturn.Add("10 4");
            WillReturn.Add("5 7");
            WillReturn.Add("4 7");
            WillReturn.Add("5 5");
            WillReturn.Add("4 3");
            WillReturn.Add("6 1");
            WillReturn.Add("1 6");
            WillReturn.Add("2 7");
            WillReturn.Add("6 7");
            WillReturn.Add("1 3");
            WillReturn.Add("6 3");
            WillReturn.Add("2 12");
            WillReturn.Add("9 6");
            WillReturn.Add("7 3");
            WillReturn.Add("3 11");
            WillReturn.Add("9 7");
            //Yes
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    struct XYInfoDef
    {
        internal long X;
        internal long Y;
    }
    static List<XYInfoDef> mXYInfoList = new List<XYInfoDef>();

    static long UB_X;
    static long UB_Y;

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

        long[] wkArr = { };
        Action<string> SplitAct = pStr =>
            wkArr = pStr.Split(' ').Select(pX => long.Parse(pX)).ToArray();

        SplitAct(InputList[0]);
        UB_X = wkArr[1] - 1;
        UB_Y = wkArr[0] - 1;

        var XYSet = new HashSet<long>();

        foreach (string EachStr in InputList.Skip(1)) {
            SplitAct(EachStr);
            long X = wkArr[1] - 1;
            long Y = wkArr[0] - 1;
            XYInfoDef WillAdd;
            WillAdd.X = X;
            WillAdd.Y = Y;
            mXYInfoList.Add(WillAdd);

            long Hash = GetHash(X, Y);
            XYSet.Add(Hash);
        }

        var Stk = new Stack<JyoutaiDef>();
        JyoutaiDef WillPush;

        foreach (XYInfoDef EachXYInfo in mXYInfoList) {
            if (EachXYInfo.X == UB_X || EachXYInfo.Y == 0) {
                WillPush.CurrX = EachXYInfo.X;
                WillPush.CurrY = EachXYInfo.Y;
                Stk.Push(WillPush);
            }
        }

        var VisitedSet = new HashSet<long>();

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

            // クリア判定
            if (Popped.CurrX == 0 || Popped.CurrY == UB_Y) {
                Console.WriteLine("No");
                return;
            }

            List<PointDef> KinbouList = Get8KinbouList(Popped.CurrX, Popped.CurrY);
            foreach (PointDef EachPoint in KinbouList) {
                long Hash = GetHash(EachPoint.X, EachPoint.Y);
                if (XYSet.Contains(Hash) == false) {
                    continue;
                }
                if (VisitedSet.Add(Hash)) {
                    WillPush.CurrX = EachPoint.X;
                    WillPush.CurrY = EachPoint.Y;
                    Stk.Push(WillPush);
                }
            }
        }
        Console.WriteLine("Yes");
    }

    // 座標のハッシュ値
    static long GetHash(long pX, long pY)
    {
        long Hash = 0;
        Hash += pX * 100000000;
        Hash += pY;
        return Hash;
    }

    struct JyoutaiDef
    {
        internal long CurrX;
        internal long CurrY;
    }

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

    // 8近傍の座標を返す
    static List<PointDef> Get8KinbouList(long pX, long pY)
    {
        var WillReturn = new List<PointDef>();
        WillReturn.AddRange(GetPoint(pX - 1, pY - 1));
        WillReturn.AddRange(GetPoint(pX + 0, pY - 1));
        WillReturn.AddRange(GetPoint(pX + 1, pY - 1));

        WillReturn.AddRange(GetPoint(pX - 1, pY + 0));
        WillReturn.AddRange(GetPoint(pX + 1, pY + 0));

        WillReturn.AddRange(GetPoint(pX - 1, pY + 1));
        WillReturn.AddRange(GetPoint(pX + 0, pY + 1));
        WillReturn.AddRange(GetPoint(pX + 1, pY + 1));

        return WillReturn;
    }

    static List<PointDef> GetPoint(long pTargetX, long pTargetY)
    {
        var WillReturn = new List<PointDef>();
        if (pTargetX < 0 || UB_X < pTargetX) return WillReturn;
        if (pTargetY < 0 || UB_Y < pTargetY) return WillReturn;

        PointDef WillAdd;
        WillAdd.X = pTargetX;
        WillAdd.Y = pTargetY;
        WillReturn.Add(WillAdd);
        return WillReturn;
    }
}

解説

ニコリのナンバーリンクの感覚で
スタートからゴールまでの経路を遮断できるかを
DFSで判定してます。