ABC222-D Between Two Arrays

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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("2");
            WillReturn.Add("1 1");
            WillReturn.Add("2 3");
            //5
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("3");
            WillReturn.Add("2 2 2");
            WillReturn.Add("2 2 2");
            //1
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("10");
            WillReturn.Add("1 2 3 4 5 6 7 8 9 10");
            WillReturn.Add("1 4 9 16 25 36 49 64 81 100");
            //978222082
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    const int Hou = 998244353;

    static void Main()
    {
        List<string> InputList = GetInputList();
        int[] AArr = InputList[1].Split(' ').Select(pX => int.Parse(pX)).ToArray();
        int[] BArr = InputList[2].Split(' ').Select(pX => int.Parse(pX)).ToArray();
        int UB = AArr.GetUpperBound(0);

        // 場合の数[直近の値]なDP表
        int[] PrevDP = new int[3000 + 1];
        PrevDP[0] = 1;

        for (int I = 0; I <= UB; I++) {
            int[] CurrDP = new int[3000 + 1];
            for (int J = 0; J <= CurrDP.GetUpperBound(0); J++) {
                if (PrevDP[J] == 0) continue;

                // 配るDPで配れる区間を求め、いもす法で配る
                int RangeMin = AArr[I];
                int RangeMax = BArr[I];
                if (RangeMin > RangeMax) continue;

                if (J <= RangeMax) {
                    RangeMin = Math.Max(RangeMin, J);
                    CurrDP[RangeMin] += PrevDP[J];
                    CurrDP[RangeMin] %= Hou;
                    if (RangeMax + 1 <= CurrDP.GetUpperBound(0)) {
                        CurrDP[RangeMax + 1] -= PrevDP[J];
                        CurrDP[RangeMax + 1] %= Hou;
                    }
                }
            }

            // いもす法の累積和を求める
            for (int J = 1; J <= CurrDP.GetUpperBound(0); J++) {
                CurrDP[J] += CurrDP[J - 1];
                CurrDP[J] %= Hou;
                if (CurrDP[J] < 0) CurrDP[J] += Hou;
            }

            PrevDP = CurrDP;
        }

        int Answer = 0;
        foreach (int EachInt in PrevDP) {
            Answer += EachInt;
            Answer %= Hou;
        }
        Console.WriteLine(Answer);
    }
}

解説

配るDPですが、いもす法で配ってます。