ABC128-D equeue

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 4");
            WillReturn.Add("-10 8 2 1 2 6");
            //14
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("6 4");
            WillReturn.Add("-6 -100 50 -2 -5 -3");
            //44
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("6 3");
            WillReturn.Add("-6 -100 50 -2 -5 -3");
            //0
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static int[] mVArr;
    static int UB;

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

        int[] wkArr = InputList[0].Split(' ').Select(pX => int.Parse(pX)).ToArray();
        int K = wkArr[1];

        mVArr = InputList[1].Split(' ').Select(pX => int.Parse(pX)).ToArray();
        UB = mVArr.GetUpperBound(0);

        int Answer = int.MinValue;
        for (int A = 0; A <= K; A++) {
            for (int B = 0; A + B <= K; B++) {
                for (int C = 0; A + B + C <= K; C++) {
                    Answer = Math.Max(Answer, DeriveScore(A, B, C));
                }
            }
        }
        Console.WriteLine(Answer);
    }

    // 左からA個取って、右からB個取って、C個捨てた時の得点を返す
    static int DeriveScore(int pA, int pB, int pC)
    {
        var TakeList = new List<int>();

        if (pA + pB < mVArr.Length) {
            TakeList.AddRange(mVArr.Take(pA));

            for (int I = UB; UB - pB + 1 <= I; I--) {
                TakeList.Add(mVArr[I]);
            }
        }
        else {
            TakeList = mVArr.ToList();
        }

        TakeList.Sort();
        for (int I = 1; I <= pC; I++) {
            if (TakeList.Count > 0 && TakeList[0] < 0) {
                TakeList.RemoveAt(0);
            }
            else break;
        }

        return TakeList.Sum();
    }
}

解説

捨てる処理は最後にまとめてやっても問題ないので

左から取る個数。右から取る個数。捨てる個数
を全探索してます。