ABC417-E A Path in A Dictionary

問題へのリンク

C#のソース

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("2");
            WillReturn.Add("6 10 3 5");
            WillReturn.Add("1 2");
            WillReturn.Add("1 3");
            WillReturn.Add("1 5");
            WillReturn.Add("1 6");
            WillReturn.Add("2 4");
            WillReturn.Add("2 5");
            WillReturn.Add("2 6");
            WillReturn.Add("3 4");
            WillReturn.Add("3 5");
            WillReturn.Add("5 6");
            WillReturn.Add("3 2 3 2");
            WillReturn.Add("1 3");
            WillReturn.Add("2 3");
            //3 1 2 5
            //3 2
        }
        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();
    }

    // 隣接リスト
    static Dictionary<long, List<long>> mToNodeListDict = new Dictionary<long, List<long>>();

    static long mStaNode;
    static long mGoalNode;

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

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

        long CurrInd = 1;
        while (CurrInd < InputList.Count - 1) {
            SplitAct(InputList[(int)CurrInd]);
            long M = wkArr[1];
            mStaNode = wkArr[2];
            mGoalNode = wkArr[3];
            mToNodeListDict.Clear();

            for (long I = CurrInd + 1; I <= CurrInd + M; I++) {
                SplitAct(InputList[(int)I]);

                long FromNode = wkArr[0];
                long ToNode = wkArr[1];

                if (mToNodeListDict.ContainsKey(FromNode) == false) {
                    mToNodeListDict[FromNode] = new List<long>();
                }
                if (mToNodeListDict.ContainsKey(ToNode) == false) {
                    mToNodeListDict[ToNode] = new List<long>();
                }
                mToNodeListDict[FromNode].Add(ToNode);
                mToNodeListDict[ToNode].Add(FromNode);
            }
            CurrInd += M + 1;

            string Result = Solve();
            Result = Regex.Replace(Result, @"(?<= )0+", "");
            Console.WriteLine(Result);
        }
    }

    static string Solve()
    {
        var InsPQueue = new PQueue_Arr();

        // 距離合計[確定ノード]なDict
        var KakuteiNodeDict = new Dictionary<long, string>();
        KakuteiNodeDict.Add(mStaNode, mStaNode.ToString());

        // Enqueue処理
        Action<long> EnqueueAct = pFromNode =>
        {
            if (mToNodeListDict.ContainsKey(pFromNode) == false) {
                return;
            }
            foreach (long EachToNode in mToNodeListDict[pFromNode]) {
                // 確定ノードならContinue
                if (KakuteiNodeDict.ContainsKey(EachToNode)) continue;

                string CurrPath = KakuteiNodeDict[pFromNode] +
                    " " + EachToNode.ToString().PadLeft(4, '0');

                PQueue_Arr.PQueueJyoutaiDef WillEnqueue;
                WillEnqueue.Node = EachToNode;
                WillEnqueue.StrSortKey = CurrPath;
                InsPQueue.Enqueue(WillEnqueue);
            }
        };
        EnqueueAct(mStaNode);

        while (InsPQueue.IsEmpty() == false) {
            PQueue_Arr.PQueueJyoutaiDef Dequeued = InsPQueue.Dequeue();

            // 確定ノードならcontinue
            if (KakuteiNodeDict.ContainsKey(Dequeued.Node)) continue;

            // 枝切り
            if (KakuteiNodeDict.ContainsKey(mGoalNode)) break;

            KakuteiNodeDict.Add(Dequeued.Node, Dequeued.StrSortKey);
            EnqueueAct(Dequeued.Node);
        }

        return KakuteiNodeDict[mGoalNode];
    }
}

#region PQueue_Arr
// 内部で配列使用の優先度付きキュー
internal class PQueue_Arr
{
    internal struct PQueueJyoutaiDef
    {
        internal long Node;
        internal string StrSortKey;
    }

    private PQueueJyoutaiDef[] mHeapArr;
    private long mHeapArrCnt = 0;

    // コンストラクタ
    internal PQueue_Arr()
    {
        mHeapArr = new PQueueJyoutaiDef[65535];
    }
    internal bool IsEmpty()
    {
        return mHeapArrCnt == 0;
    }

    // エンキュー処理
    internal void Enqueue(PQueueJyoutaiDef pAddJyoutai)
    {
        long CurrNode = 1 + mHeapArrCnt;
        if (mHeapArr.GetUpperBound(0) < CurrNode) {
            ExtendArr();
        }
        mHeapArr[CurrNode] = pAddJyoutai;
        mHeapArrCnt++;

        while (1 < CurrNode &&
            mHeapArr[CurrNode / 2].StrSortKey.CompareTo(mHeapArr[CurrNode].StrSortKey) > 0) {
            PQueueJyoutaiDef Swap = mHeapArr[CurrNode];
            mHeapArr[CurrNode] = mHeapArr[CurrNode / 2];
            mHeapArr[CurrNode / 2] = Swap;

            CurrNode /= 2;
        }
    }

    // 配列のExtend
    private void ExtendArr()
    {
        PQueueJyoutaiDef[] NewHeapArr = new PQueueJyoutaiDef[mHeapArrCnt * 2];
        mHeapArr.CopyTo(NewHeapArr, 0);
        mHeapArr = NewHeapArr;
    }

    // デキュー処理
    internal PQueueJyoutaiDef Dequeue()
    {
        PQueueJyoutaiDef TopNode = mHeapArr[1];
        long LastNode = mHeapArrCnt;
        mHeapArr[1] = mHeapArr[LastNode];
        mHeapArrCnt--;

        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(long pRootNode)
    {
        if (mHeapArrCnt <= 1) {
            return;
        }

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

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

        if (Left <= mHeapArrCnt && mHeapArr[Left].StrSortKey.CompareTo(Smallest) < 0) {
            Smallest = mHeapArr[Left].StrSortKey;
            SmallestNode = Left;
        }
        if (Right <= mHeapArrCnt && mHeapArr[Right].StrSortKey.CompareTo(Smallest) < 0) {
            Smallest = mHeapArr[Right].StrSortKey;
            SmallestNode = Right;
        }

        // 子ノードのほうが大きい場合
        if (SmallestNode != pRootNode) {
            PQueueJyoutaiDef Swap = mHeapArr[SmallestNode];
            mHeapArr[SmallestNode] = mHeapArr[pRootNode];
            mHeapArr[pRootNode] = Swap;

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

解説

経路(ノードを前ゼロ埋めして、半角空白区切り)
をコストとしたダイクストラ法で
最後に正規表現で、前ゼロを消してます。