ABC302-E Isolation

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("3 7");
            WillReturn.Add("1 1 2");
            WillReturn.Add("1 1 3");
            WillReturn.Add("1 2 3");
            WillReturn.Add("2 1");
            WillReturn.Add("1 1 2");
            WillReturn.Add("2 2");
            WillReturn.Add("1 1 2");
            //1
            //0
            //0
            //1
            //0
            //3
            //1
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2 1");
            WillReturn.Add("2 1");
            //2
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

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

    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];

        foreach (string EachStr in InputList.Skip(1)) {
            SplitAct(EachStr);
            int Type = wkArr[0];
            if (Type == 1) {
                int FromNode = wkArr[1];
                int ToNode = wkArr[2];

                if (mToNodeListDict.ContainsKey(FromNode) == false) {
                    mToNodeListDict[FromNode] = new HashSet<int>();
                }
                mToNodeListDict[FromNode].Add(ToNode);

                if (mToNodeListDict.ContainsKey(ToNode) == false) {
                    mToNodeListDict[ToNode] = new HashSet<int>();
                }
                mToNodeListDict[ToNode].Add(FromNode);
            }
            if (Type == 2) {
                int CurrNode = wkArr[1];
                if (mToNodeListDict.ContainsKey(CurrNode)) {
                    var DelKouho = new List<int>();
                    foreach (int EachNode in mToNodeListDict[CurrNode]) {
                        if (mToNodeListDict.ContainsKey(EachNode)) {
                            mToNodeListDict[EachNode].Remove(CurrNode);
                            DelKouho.Add(EachNode);
                        }
                    }
                    foreach (int Each in DelKouho) {
                        if (mToNodeListDict[Each].Count == 0) {
                            mToNodeListDict.Remove(Each);
                        }
                    }
                }
                mToNodeListDict.Remove(CurrNode);
            }
            Console.WriteLine(N - mToNodeListDict.Count);
        }
    }
}

解説

クエリ2では、クエリ1で追加した辺しか削除しないので、
隣接リストをHashSetで管理すれば、間に合います。