square869120コンテスト1 C問題 お金の街

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("6 6");
            WillReturn.Add("1");
            WillReturn.Add("2");
            WillReturn.Add("3");
            WillReturn.Add("4");
            WillReturn.Add("5");
            WillReturn.Add("7");
            WillReturn.Add("1 2");
            WillReturn.Add("1 3");
            WillReturn.Add("1 6");
            WillReturn.Add("2 4");
            WillReturn.Add("3 4");
            WillReturn.Add("4 5");
            //20
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4 2");
            WillReturn.Add("1");
            WillReturn.Add("10");
            WillReturn.Add("5");
            WillReturn.Add("6");
            WillReturn.Add("1 2");
            WillReturn.Add("3 4");
            //11
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("5 4");
            WillReturn.Add("2");
            WillReturn.Add("3");
            WillReturn.Add("5");
            WillReturn.Add("6");
            WillReturn.Add("7");
            WillReturn.Add("1 3");
            WillReturn.Add("1 4");
            WillReturn.Add("2 4");
            WillReturn.Add("4 5");
            //20
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static long[] mDArr;

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

    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]);
        long N = wkArr[0];
        long K = wkArr[1];

        mDArr = InputList.Skip(1).Take((int)N).Select(pX => long.Parse(pX)).ToArray();

        foreach (string EachStr in InputList.Skip(1 + (int)N)) {
            SplitAct(EachStr);
            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);
        }

        var ResultList = new List<long>();
        for (long I = 1; I <= N; I++) {
            ResultList.Add(ExecDFS(I));
        }
        Console.WriteLine(ResultList.Max());
    }

    struct JyoutaiDef
    {
        internal long CurrNode;
        internal long VisitedSet;
        internal long ScoreSum;
    }

    // 始点を引数として、DFSを行う
    static long ExecDFS(long pStaNode)
    {
        long WillReturn = long.MinValue;

        var Stk = new Stack<JyoutaiDef>();
        JyoutaiDef WillPush;
        WillPush.CurrNode = pStaNode;
        WillPush.VisitedSet = (1L << (int)pStaNode);
        WillPush.ScoreSum = mDArr[pStaNode - 1];
        Stk.Push(WillPush);

        while (Stk.Count > 0) {
            JyoutaiDef Popped = Stk.Pop();
            WillReturn = Math.Max(WillReturn, Popped.ScoreSum);

            if (mToNodeListDict.ContainsKey(Popped.CurrNode)) {
                foreach (long EachToNode in mToNodeListDict[Popped.CurrNode]) {
                    long CurrBit = (1L << (int)EachToNode);
                    if ((Popped.VisitedSet & CurrBit) > 0) continue;

                    WillPush.VisitedSet = Popped.VisitedSet | CurrBit;
                    WillPush.CurrNode = EachToNode;
                    WillPush.ScoreSum = Popped.ScoreSum + mDArr[EachToNode - 1];
                    Stk.Push(WillPush);
                }
            }
        }
        return WillReturn;
    }
}

解説

全ての始点からのDFSを試してます。
ノード数は50以下なので
long型のBitSetで再訪を防止してます。