ABC374-C Separated Lunch

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("5");
            WillReturn.Add("2 3 5 10 12");
            //17
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("2");
            WillReturn.Add("1 1");
            //1
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("6");
            WillReturn.Add("22 25 26 45 22 31");
            //89
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();
        int K = int.Parse(InputList[0]);
        long[] KArr = InputList[1].Split(' ').Select(pX => long.Parse(pX)).ToArray();

        var BaseList = new List<long>();
        BaseList.Add(0);
        BaseList.Add(1);

        var AnswerList = new List<long>();
        foreach (long[] EachArr in RubyPatternClass<long>.RepeatedPermutation(BaseList, K)) {
            long Sum0 = 0;
            long Sum1 = 0;
            for (int I = 0; I <= KArr.GetUpperBound(0); I++) {
                if (EachArr[I] == 0) Sum0 += KArr[I];
                if (EachArr[I] == 1) Sum1 += KArr[I];
            }
            AnswerList.Add(Math.Max(Sum0, Sum1));
        }
        Console.WriteLine(AnswerList.Min());
    }
}

#region RubyPatternClass
// Rubyの場合の数
internal static class RubyPatternClass<Type>
{
    // 重複順列を返す
    private struct JyoutaiDef_RepeatedPermutation
    {
        internal List<int> SelectedIndList;
    }
    internal static IEnumerable<Type[]> RepeatedPermutation(IEnumerable<Type> pEnum, int pR)
    {
        if (pR == 0) yield break;
        Type[] pArr = pEnum.ToArray();

        var Stk = new Stack<JyoutaiDef_RepeatedPermutation>();
        JyoutaiDef_RepeatedPermutation WillPush;
        for (int I = pArr.GetUpperBound(0); 0 <= I; I--) {
            WillPush.SelectedIndList = new List<int>() { I };
            Stk.Push(WillPush);
        }

        while (Stk.Count > 0) {
            JyoutaiDef_RepeatedPermutation Popped = Stk.Pop();

            // クリア判定
            if (Popped.SelectedIndList.Count == pR) {
                var WillReturn = new List<Type>();
                Popped.SelectedIndList.ForEach(X => WillReturn.Add(pArr[X]));
                yield return WillReturn.ToArray();
                continue;
            }

            for (int I = pArr.GetUpperBound(0); 0 <= I; I--) {
                WillPush.SelectedIndList = new List<int>(Popped.SelectedIndList) { I };
                Stk.Push(WillPush);
            }
        }
    }
}
#endregion

解説

0と1からなる重複順列を求めて、解候補を列挙してます。