DPL_1_A: Coin Changing Problem

問題へのリンク

C#のソース

using System;
using System.Collections.Generic;
using System.Linq;

// Q073 コイン問題 https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=DPL_1_A&lang=jp
class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("15 6");
            WillReturn.Add("1 2 7 8 12 50");
            //2
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("65 6");
            WillReturn.Add("1 2 7 8 12 50");
            //3
        }
        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 N = wkArr[0];
        int UB = N;

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

        // 最小枚数[金額]なDP表
        int?[] DPArr = new int?[UB + 1];
        DPArr[0] = 0;

        foreach (int EachCoin in CArr) {
            for (int I = 0; I <= UB; I++) {
                if (DPArr[I].HasValue == false) {
                    continue;
                }
                int NewInd = EachCoin + I;
                if (NewInd > UB) break;

                int NewVal = DPArr[I].Value + 1;

                if (DPArr[NewInd].HasValue) {
                    if (DPArr[NewInd].Value > NewVal) {
                        DPArr[NewInd] = NewVal;
                    }
                }
                else {
                    DPArr[NewInd] = NewVal;
                }
            }
        }
        Console.WriteLine(DPArr[UB]);
    }
}

解説

動的計画法で解いてます。