ABC141-D Powerful Discount Tickets

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 3");
            WillReturn.Add("2 13 8");
            //9
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4 4");
            WillReturn.Add("1 9 3 5");
            //6
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("1 100000");
            WillReturn.Add("1000000000");
            //0
        }
        else if (InputPattern == "Input4") {
            WillReturn.Add("10 1");
            WillReturn.Add("1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000 1000000000");
            //9500000000
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

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

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

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

        PQueue.PQueueJyoutaiDef WillEnqueue;
        var InsPQueue = new PQueue();
        foreach (int EachInt in AArr) {
            WillEnqueue.Cost = EachInt;
            InsPQueue.Enqueue(WillEnqueue);
        }

        long Answer = 0;
        while (InsPQueue.IsEmpty() == false) {
            PQueue.PQueueJyoutaiDef Dequeued = InsPQueue.Dequeue();
            if (Dequeued.Cost == 0) continue;

            if (RestM > 0) {
                WillEnqueue.Cost = Dequeued.Cost / 2;
                InsPQueue.Enqueue(WillEnqueue);
                RestM--;
                continue;
            }
            Answer += Dequeued.Cost;
        }
        Console.WriteLine(Answer);
    }
}

#region PQueue
// 優先度付きキュー (根のCostが最大)
internal class PQueue
{
    internal struct PQueueJyoutaiDef
    {
        internal int Cost;
    }

    private Dictionary<int, PQueueJyoutaiDef> mHeapDict = new Dictionary<int, PQueueJyoutaiDef>();

    internal bool IsEmpty()
    {
        return mHeapDict.Count == 0;
    }

    // エンキュー処理
    internal void Enqueue(PQueueJyoutaiDef pAddJyoutai)
    {
        int CurrNode = 1 + mHeapDict.Count;
        mHeapDict[CurrNode] = pAddJyoutai;

        while (1 < CurrNode && mHeapDict[CurrNode / 2].Cost < mHeapDict[CurrNode].Cost) {
            PQueueJyoutaiDef Swap = mHeapDict[CurrNode];
            mHeapDict[CurrNode] = mHeapDict[CurrNode / 2];
            mHeapDict[CurrNode / 2] = Swap;

            CurrNode /= 2;
        }
    }

    // デキュー処理
    internal PQueueJyoutaiDef Dequeue()
    {
        PQueueJyoutaiDef TopNode = mHeapDict[1];
        int LastNode = mHeapDict.Count;
        mHeapDict[1] = mHeapDict[LastNode];
        mHeapDict.Remove(LastNode);

        MinHeapify(1);
        return TopNode;
    }

    // 根ノードを指定し、根から葉へヒープ構築
    private void MinHeapify(int pRootNode)
    {
        if (mHeapDict.Count <= 1) {
            return;
        }

        int Left = pRootNode * 2;
        int Right = pRootNode * 2 + 1;

        // 左の子、自分、右の子で値が最大のノードを選ぶ
        int Smallest = mHeapDict[pRootNode].Cost;
        int SmallestNode = pRootNode;

        if (mHeapDict.ContainsKey(Left) && mHeapDict[Left].Cost > Smallest) {
            Smallest = mHeapDict[Left].Cost;
            SmallestNode = Left;
        }
        if (mHeapDict.ContainsKey(Right) && mHeapDict[Right].Cost > Smallest) {
            Smallest = mHeapDict[Right].Cost;
            SmallestNode = Right;
        }

        // 子ノードのほうが大きい場合
        if (SmallestNode != pRootNode) {
            PQueueJyoutaiDef Swap = mHeapDict[SmallestNode];
            mHeapDict[SmallestNode] = mHeapDict[pRootNode];
            mHeapDict[pRootNode] = Swap;

            // 再帰的に呼び出し
            MinHeapify(SmallestNode);
        }
    }
}
#endregion

解説

プライオリティキューを使って
最大値を半分にする処理を繰り返してます。