AOJ 0635 ヘビの JOI 君 (Snake JOI)

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("8 10 4");
            WillReturn.Add("0");
            WillReturn.Add("1");
            WillReturn.Add("1");
            WillReturn.Add("2");
            WillReturn.Add("1");
            WillReturn.Add("1");
            WillReturn.Add("2");
            WillReturn.Add("0");
            WillReturn.Add("1 2 1");
            WillReturn.Add("1 3 1");
            WillReturn.Add("2 3 3");
            WillReturn.Add("2 4 5");
            WillReturn.Add("3 4 1");
            WillReturn.Add("4 5 1");
            WillReturn.Add("5 6 1");
            WillReturn.Add("5 8 1");
            WillReturn.Add("1 7 2");
            WillReturn.Add("7 8 2");
            //9
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("15 25 4");
            WillReturn.Add("0");
            WillReturn.Add("1");
            WillReturn.Add("1");
            WillReturn.Add("0");
            WillReturn.Add("2");
            WillReturn.Add("1");
            WillReturn.Add("0");
            WillReturn.Add("1");
            WillReturn.Add("1");
            WillReturn.Add("2");
            WillReturn.Add("0");
            WillReturn.Add("0");
            WillReturn.Add("1");
            WillReturn.Add("0");
            WillReturn.Add("1");
            WillReturn.Add("8 11 1");
            WillReturn.Add("7 10 1");
            WillReturn.Add("12 14 1");
            WillReturn.Add("3 8 1");
            WillReturn.Add("1 5 1");
            WillReturn.Add("3 9 1");
            WillReturn.Add("3 8 1");
            WillReturn.Add("1 5 1");
            WillReturn.Add("6 15 1");
            WillReturn.Add("11 12 1");
            WillReturn.Add("2 14 1");
            WillReturn.Add("7 10 1");
            WillReturn.Add("11 12 1");
            WillReturn.Add("5 13 1");
            WillReturn.Add("2 8 1");
            WillReturn.Add("1 4 1");
            WillReturn.Add("2 11 1");
            WillReturn.Add("5 6 1");
            WillReturn.Add("1 13 1");
            WillReturn.Add("6 12 1");
            WillReturn.Add("5 10 1");
            WillReturn.Add("9 13 1");
            WillReturn.Add("4 10 1");
            WillReturn.Add("3 12 1");
            WillReturn.Add("7 13 1");
            //6
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static long[] GetSplitArr(string pStr)
    {
        return (pStr == "" ? new string[0] : pStr.Split(' ')).Select(pX => long.Parse(pX)).ToArray();
    }

    struct EdgeInfoDef
    {
        internal long ToNode;
        internal long Cost;
    }
    static Dictionary<long, List<EdgeInfoDef>> mEdgeInfoListDict = new Dictionary<long, List<EdgeInfoDef>>();

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

        long[] wkArr = { };
        Action<string> SplitAct = (pStr) => wkArr = GetSplitArr(pStr);

        SplitAct(InputList[0]);
        long N = wkArr[0];
        long X = wkArr[2];

        // 温度[ノード]
        var OndoDict = new Dictionary<long, long>();

        for (long I = 1; I <= N; I++) {
            OndoDict[I] = long.Parse(InputList[(int)I]);
        }

        foreach (string EachStr in InputList.Skip(1 + (int)N)) {
            SplitAct(EachStr);
            long A = wkArr[0];
            long B = wkArr[1];
            long C = wkArr[2];

            Action<long, long, long> AddEdgeAct = (pFromNode, pToNode, pCost) =>
            {
                if (mEdgeInfoListDict.ContainsKey(pFromNode) == false) {
                    mEdgeInfoListDict[pFromNode] = new List<EdgeInfoDef>();
                }
                EdgeInfoDef WillAdd;
                WillAdd.ToNode = pToNode;
                WillAdd.Cost = pCost;
                mEdgeInfoListDict[pFromNode].Add(WillAdd);
            };
            AddEdgeAct(A, B, C);
            AddEdgeAct(B, A, C);
        }

        var InsPQueue = new PQueue();
        PQueue.PQueueJyoutaiDef WillEnqueue;
        WillEnqueue.CurrNode = 1;
        WillEnqueue.CurrJyoutai = 0;
        WillEnqueue.RestTime = X;
        WillEnqueue.Val = 0;
        InsPQueue.Enqueue(WillEnqueue);

        var VisitedSet = new HashSet<string>();

        while (InsPQueue.Count() > 0) {
            PQueue.PQueueJyoutaiDef Dequeued = InsPQueue.Dequeue();

            // クリア判定
            if (Dequeued.CurrNode == N) {
                Console.WriteLine(Dequeued.Val);
                return;
            }

            // 枝切り
            string Hash = string.Format("{0},{1},{2}",
                Dequeued.CurrNode, Dequeued.CurrJyoutai, Dequeued.RestTime);

            if (VisitedSet.Add(Hash) == false) {
                continue;
            }

            foreach (EdgeInfoDef EachEdgeInfo in mEdgeInfoListDict[Dequeued.CurrNode]) {
                long NewNode = EachEdgeInfo.ToNode;
                WillEnqueue.CurrNode = NewNode;
                WillEnqueue.CurrJyoutai = Dequeued.CurrJyoutai;
                WillEnqueue.RestTime = Dequeued.RestTime - EachEdgeInfo.Cost;
                WillEnqueue.RestTime = Math.Max(0, WillEnqueue.RestTime);

                if (WillEnqueue.RestTime == 0) {
                    WillEnqueue.CurrJyoutai = 1;
                }

                if (OndoDict[NewNode] == 0 && WillEnqueue.CurrJyoutai == 2) {
                    continue;
                }
                if (OndoDict[NewNode] == 2 && WillEnqueue.CurrJyoutai == 0) {
                    continue;
                }

                if (OndoDict[NewNode] == 0) {
                    WillEnqueue.CurrJyoutai = 0;
                    WillEnqueue.RestTime = X;
                }
                if (OndoDict[NewNode] == 2) {
                    WillEnqueue.CurrJyoutai = 2;
                    WillEnqueue.RestTime = X;
                }

                WillEnqueue.Val = Dequeued.Val + EachEdgeInfo.Cost;

                InsPQueue.Enqueue(WillEnqueue);
            }
        }
    }
}

#region PQueue
// 優先度付きキュー (根のValが最小)
internal class PQueue
{
    internal struct PQueueJyoutaiDef
    {
        internal long CurrNode;
        internal long CurrJyoutai;
        internal long RestTime;
        internal long Val;
    }

    private Dictionary<int, PQueueJyoutaiDef> mHeapDict = new Dictionary<int, PQueueJyoutaiDef>();

    internal bool IsEmpty()
    {
        return mHeapDict.Count == 0;
    }

    internal long Count()
    {
        return mHeapDict.Count;
    }

    internal long Peek()
    {
        return mHeapDict[1].Val;
    }

    // エンキュー処理
    internal void Enqueue(PQueueJyoutaiDef pAddJyoutai)
    {
        int CurrNode = 1 + mHeapDict.Count;
        mHeapDict[CurrNode] = pAddJyoutai;

        while (1 < CurrNode && mHeapDict[CurrNode / 2].Val > mHeapDict[CurrNode].Val) {
            PQueueJyoutaiDef Swap = mHeapDict[CurrNode];
            mHeapDict[CurrNode] = mHeapDict[CurrNode / 2];
            mHeapDict[CurrNode / 2] = Swap;

            CurrNode /= 2;
        }
    }

    // デキュー処理
    internal PQueueJyoutaiDef Dequeue()
    {
        PQueueJyoutaiDef TopNode = mHeapDict[1];
        int LastNode = mHeapDict.Count;
        mHeapDict[1] = mHeapDict[LastNode];
        mHeapDict.Remove(LastNode);

        MinHeapify(1);
        return TopNode;
    }

    // 根ノードを指定し、根から葉へヒープ構築
    private void MinHeapify(int pRootNode)
    {
        if (mHeapDict.Count <= 1) {
            return;
        }

        int Left = pRootNode * 2;
        int Right = pRootNode * 2 + 1;

        // 左の子、自分、右の子で値が最小のノードを選ぶ
        long Smallest = mHeapDict[pRootNode].Val;
        int SmallestNode = pRootNode;

        if (mHeapDict.ContainsKey(Left) && mHeapDict[Left].Val < Smallest) {
            Smallest = mHeapDict[Left].Val;
            SmallestNode = Left;
        }
        if (mHeapDict.ContainsKey(Right) && mHeapDict[Right].Val < Smallest) {
            Smallest = mHeapDict[Right].Val;
            SmallestNode = Right;
        }

        // 子ノードのほうが小さい場合
        if (SmallestNode != pRootNode) {
            PQueueJyoutaiDef Swap = mHeapDict[SmallestNode];
            mHeapDict[SmallestNode] = mHeapDict[pRootNode];
            mHeapDict[pRootNode] = Swap;

            // 再帰的に呼び出し
            MinHeapify(SmallestNode);
        }
    }
}
#endregion

解説

{現在ノード , 状態 , 状態解除までの残時間}
の再訪防止で枝切りしつつ、
コストの昇順でBFSしてます。