ABC183-C Travel

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("4 330");
            WillReturn.Add("0 1 10 100");
            WillReturn.Add("1 0 20 200");
            WillReturn.Add("10 20 0 300");
            WillReturn.Add("100 200 300 0");
            //2
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("5 5");
            WillReturn.Add("0 1 1 1 1");
            WillReturn.Add("1 0 1 1 1");
            WillReturn.Add("1 1 0 1 1");
            WillReturn.Add("1 1 1 0 1");
            WillReturn.Add("1 1 1 1 0");
            //24
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    struct JyoutaiDef
    {
        internal int CurrPos;
        internal HashSet<int> VisitedSet;
        internal int CostSum;
    }

    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 K = wkArr[1];

        int UB = N - 1;
        int[,] MatrixArr = new int[UB + 1, UB + 1];

        for (int I = 0; I <= UB; I++) {
            SplitAct(InputList[1 + I]);
            for (int J = 0; J <= UB; J++) {
                MatrixArr[J, I] = wkArr[J];
            }
        }

        var Stk = new Stack<JyoutaiDef>();
        JyoutaiDef WillPush;
        WillPush.CurrPos = 0;
        WillPush.VisitedSet = new HashSet<int>();
        WillPush.CostSum = 0;
        Stk.Push(WillPush);

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

            if (Popped.VisitedSet.Count == N) {
                if (Popped.CurrPos == 0 && Popped.CostSum == K) {
                    Answer++;
                }
                continue;
            }

            for (int I = 0; I <= UB; I++) {
                if (Popped.VisitedSet.Contains(I)) continue;

                WillPush.CurrPos = I;
                WillPush.CostSum = Popped.CostSum + MatrixArr[Popped.CurrPos, I];
                WillPush.VisitedSet = new HashSet<int>(Popped.VisitedSet);
                WillPush.VisitedSet.Add(I);
                Stk.Push(WillPush);
            }
        }
        Console.WriteLine(Answer);
    }
}

解説

深さ優先探索してます。