Educational DP Contest E Knapsack 2

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 8");
            WillReturn.Add("3 30");
            WillReturn.Add("4 50");
            WillReturn.Add("5 60");
            //90
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("1 1000000000");
            WillReturn.Add("1000000000 10");
            //10
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("6 15");
            WillReturn.Add("6 5");
            WillReturn.Add("5 6");
            WillReturn.Add("6 4");
            WillReturn.Add("6 6");
            WillReturn.Add("3 5");
            WillReturn.Add("7 2");
            //17
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    struct WVInfoDef
    {
        internal long W;
        internal long V;
    }

    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]);
        long W = wkArr[1];

        var WVInfoList = new List<WVInfoDef>();
        foreach (string EachStr in InputList.Skip(1)) {
            SplitAct(EachStr);
            WVInfoDef WillAdd;
            WillAdd.W = wkArr[0];
            WillAdd.V = wkArr[1];
            WVInfoList.Add(WillAdd);
        }

        // 最小の重さ[価値] なDP表
        long UB = WVInfoList.Sum(px => px.V);
        long?[] DPArr = new long?[UB + 1];
        DPArr[0] = 0;

        foreach (WVInfoDef EachWVInfo in WVInfoList) {
            for (long I = UB; 0 <= I; I--) {
                if (DPArr[I].HasValue == false) continue;

                long NewInd = I + EachWVInfo.V;
                long NewVal = DPArr[I].Value + EachWVInfo.W;
                if (NewVal > W) continue;

                if (DPArr[NewInd].HasValue) {
                    if (DPArr[NewInd].Value <= NewVal) {
                        continue;
                    }
                }
                DPArr[NewInd] = NewVal;
            }
        }

        for (long I = UB; 0 <= I; I--) {
            if (DPArr[I].HasValue) {
                Console.WriteLine(I);
                break;
            }
        }
    }
}

解説

価値の上限が10^3なので、
最小の重さ[価値]なDP表を使ってます。