ABC040-D 道路の老朽化対策について

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("5 4");
            WillReturn.Add("1 2 2000");
            WillReturn.Add("2 3 2004");
            WillReturn.Add("3 4 1999");
            WillReturn.Add("4 5 2001");
            WillReturn.Add("3");
            WillReturn.Add("1 2000");
            WillReturn.Add("1 1999");
            WillReturn.Add("3 1995");
            //1
            //3
            //5
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4 5");
            WillReturn.Add("1 2 2005");
            WillReturn.Add("3 1 2001");
            WillReturn.Add("3 4 2002");
            WillReturn.Add("1 4 2004");
            WillReturn.Add("4 2 2003");
            WillReturn.Add("5");
            WillReturn.Add("1 2003");
            WillReturn.Add("2 2003");
            WillReturn.Add("1 2001");
            WillReturn.Add("3 2003");
            WillReturn.Add("4 2004");
            //3
            //3
            //4
            //1
            //1
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("4 5");
            WillReturn.Add("1 2 10");
            WillReturn.Add("1 2 1000");
            WillReturn.Add("2 3 10000");
            WillReturn.Add("2 3 100000");
            WillReturn.Add("3 1 200000");
            WillReturn.Add("4");
            WillReturn.Add("1 0");
            WillReturn.Add("2 10000");
            WillReturn.Add("3 100000");
            WillReturn.Add("4 0");
            //3
            //3
            //2
            //1
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    struct QueryInfoDef
    {
        internal string Type;
        internal int Year;
        internal int P1;
        internal int P2;
    }

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

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

        SplitAct(InputList[0]);
        int N = wkArr[0];
        int M = wkArr[1];

        var QueryInfoList = new List<QueryInfoDef>();
        foreach (string EachStr in InputList.Skip(1).Take(M)) {
            SplitAct(EachStr);
            QueryInfoDef WillAdd;
            WillAdd.Type = "Unite";
            WillAdd.Year = wkArr[2];
            WillAdd.P1 = wkArr[0];
            WillAdd.P2 = wkArr[1];
            QueryInfoList.Add(WillAdd);
        }

        int KokuminNo = 1;
        foreach (string EachStr in InputList.Skip(1 + M + 1)) {
            SplitAct(EachStr);
            QueryInfoDef WillAdd;
            WillAdd.Type = "GetSize";
            WillAdd.Year = wkArr[1];
            WillAdd.P1 = wkArr[0];
            WillAdd.P2 = KokuminNo++;
            QueryInfoList.Add(WillAdd);
        }

        var Query1 = QueryInfoList.OrderByDescending(pX => pX.Year);
        var Query2 = Query1.ThenBy(pX => (pX.Type == "GetSize") ? 0 : 1);
        QueryInfoList = Query2.ToList();

        var InsUnionFindSizeInfo = new UnionFindSizeInfo();
        for (int I = 1; I <= N; I++) {
            InsUnionFindSizeInfo.MakeSet(I);
        }

        // 訪問可能ノード数[国民] なDict
        var AnswerDict = new Dictionary<int, long>();
        foreach (QueryInfoDef EachQueryInfo in QueryInfoList) {
            if (EachQueryInfo.Type == "Unite") {
                InsUnionFindSizeInfo.Unite(EachQueryInfo.P1, EachQueryInfo.P2);
            }
            if (EachQueryInfo.Type == "GetSize") {
                AnswerDict[EachQueryInfo.P2] = InsUnionFindSizeInfo.GetSize(EachQueryInfo.P1);
            }
        }

        foreach (var EachPair in AnswerDict.OrderBy(pX => pX.Key)) {
            Console.WriteLine(EachPair.Value);
        }
    }
}

// UnionFindSizeInfoクラス
internal class UnionFindSizeInfo
{
    private class NodeInfoDef
    {
        internal long ParentNode;
        internal long Rank;
        internal long Size;
    }
    private Dictionary<long, NodeInfoDef> mNodeInfoDict =
        new Dictionary<long, NodeInfoDef>();

    // 要素が1つである木を森に追加
    internal void MakeSet(long pNode)
    {
        NodeInfoDef WillAdd = new NodeInfoDef();
        WillAdd.ParentNode = pNode;
        WillAdd.Rank = 0;
        WillAdd.Size = 1;
        mNodeInfoDict[pNode] = WillAdd;
    }

    // 合併処理
    internal void Unite(long pX, long pY)
    {
        long XNode = FindSet(pX);
        long YNode = FindSet(pY);

        // 既に同じ木の場合
        if (XNode == YNode) return;

        long XRank = mNodeInfoDict[XNode].Rank;
        long YRank = mNodeInfoDict[YNode].Rank;

        if (XRank > YRank) {
            mNodeInfoDict[YNode].ParentNode = XNode;
            mNodeInfoDict[XNode].Size += mNodeInfoDict[YNode].Size;
        }
        else {
            mNodeInfoDict[XNode].ParentNode = YNode;
            mNodeInfoDict[YNode].Size += mNodeInfoDict[XNode].Size;
            if (XRank == YRank) {
                mNodeInfoDict[YNode].Rank++;
            }
        }
    }

    // ノードを引数として、木の根を取得
    internal long FindSet(long pTargetNode)
    {
        // 根までの経路上のノードのList
        var PathNodeList = new List<long>();

        long CurrNode = pTargetNode;
        while (CurrNode != mNodeInfoDict[CurrNode].ParentNode) {
            PathNodeList.Add(CurrNode);
            CurrNode = mNodeInfoDict[CurrNode].ParentNode;
        }

        // 経路圧縮 (親ポインタの付け替え)
        foreach (long EachPathNode in PathNodeList) {
            NodeInfoDef wkNodeInfo = mNodeInfoDict[EachPathNode];
            wkNodeInfo.ParentNode = CurrNode;
            mNodeInfoDict[EachPathNode] = wkNodeInfo;
        }
        return CurrNode;
    }

    // ノードを引数として、木のサイズを取得
    internal long GetSize(long pNode)
    {
        long RootNode = FindSet(pNode);
        return mNodeInfoDict[RootNode].Size;
    }

    internal void DebugPrint()
    {
        foreach (var EachPair in mNodeInfoDict.OrderBy(pX => pX.Key)) {
            Console.WriteLine("mNodeInfoDict[{0}].ParentNode={1}",
                EachPair.Key, EachPair.Value.ParentNode);
        }
    }
}

解説

UnionFindで
クエリを年の降順に処理してます。