题解 | #自动售货系统#

没啥好说的，一步步慢慢写

import java.util.*;

public class Main{

    // static int[] goods = new int[6];
    // static int[] box = new int[4];
    static int payment = 0;
    // static List<String> goodsName = List.of("A1", "A2", "A3", "A4", "A5", "A6");
    static List<String> goodsName = Arrays.asList("A1", "A2", "A3", "A4", "A5",
            "A6");
    static Map<String, Integer> goodsPrice = new HashMap<>();
    static {
        goodsPrice.put("A1", 2);
        goodsPrice.put("A2", 3);
        goodsPrice.put("A3", 4);
        goodsPrice.put("A4", 5);
        goodsPrice.put("A5", 8);
        goodsPrice.put("A6", 6);
    }
    static int[] boxName = {1, 2, 5, 10};
    static Map<String, Integer> goods = new LinkedHashMap<>();
    static Map<Integer, Integer> box = new LinkedHashMap<>();


    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        String input = scan.nextLine();
        String[] commands = input.split("\\;");

        //分别处理命令
        for (String command : commands) {
            //初始化
            if (command.startsWith("r")) System.out.println(initialize(command));
            //投币
            if (command.startsWith("p")) System.out.println(pay(command));
            //购买商品
            if (command.startsWith("b")) System.out.println(buy(command));
            //退币
            if (command.startsWith("c")) System.out.println(refund(command));
            //查询
            if (command.startsWith("q")) System.out.println(query(command));
        }

    }

    //初始化输出
    public static String initialize(String command) {
        String[] inputs = command.split(" ");
        String[] input1 = inputs[1].split("\\-");
        String[] input2 = inputs[2].split("\\-");
        for (int i = 0; i < goodsName.size(); i++) {
            goods.put(goodsName.get(i), Integer.parseInt(input1[i]));
            if (i < boxName.length) {
                box.put(boxName[i], Integer.parseInt(input2[i]));
            }
        }
        return "S001:Initialization is successful";
    }

    //投币输出
    public static String pay(String command) {
        int money = Integer.parseInt(command.split(" ")[1]);
        if (!(money == 1 || money == 2 || money == 5 ||
                money == 10)) return "E002:Denomination error";
        if (((box.get(1) + 2 * box.get(2)) < money) && (money != 1 &&
                money != 2)) return "E003:Change is not enough, pay fail";
        if (sumGoods() == 0) return "E005:All the goods sold out";
        //若成功投币
        payment += money;
        box.put(money, box.get(money) + 1);
        return "S002:Pay success,balance=" + payment + "";

    }

    //购买商品输出
    public static String buy(String command) {
        String goodsBuyed = command.split(" ")[1];
        if (!goodsName.contains(goodsBuyed)) return "E006:Goods does not exist";
        if (goods.get(goodsBuyed) == 0) return "E007:The goods sold out";
        if (payment < goodsPrice.get(goodsBuyed)) return "E008:Lack of balance";
        //购买商品成功
        payment -= goodsPrice.get(goodsBuyed);
        goods.put(goodsBuyed, goods.get(goodsBuyed) - 1);
        return "S003:Buy success,balance=" + payment + "";
    }

    //退币
    public static String refund(String command) {
        if (payment == 0) return "E009:Work failure";
        //按照退币原则进行退币
        StringBuilder sb = new StringBuilder();
        sb.append("1 yuan coin number=").append(payment % 5 % 2).append("\n").
                append("2 yuan coin number=").append(payment % 5 / 2).append("\n").
                append("5 yuan coin number=").append(payment % 10 / 5).append("\n").
                append("10 yuan coin number=").append(payment / 10);
        box.put(1,box.get(1)-payment % 5 % 2);
        box.put(2,box.get(2)-payment % 5 / 2);
        box.put(5,box.get(5)-payment % 10 / 5);
        box.put(10,box.get(10)-payment / 10);
        payment = 0;
        return sb.toString();
    }


    //查询
    public static String query(String command) {
        if(command.split(" ").length!=2) return "E010:Parameter error";
        String option = command.split(" ")[1];
        StringBuilder sb = new StringBuilder();
        if (option.equals("0")) {
            List<Map.Entry> list = new ArrayList<>(goods.entrySet());
            list.sort(new Comparator<Map.Entry>() {
                public int compare(Map.Entry e1, Map.Entry e2) {
                    if (e1.getValue() != e2.getValue()) {
                        return (int)e2.getValue() - (int)e1.getValue();
                    } else {
                        return 0;
                    }

                }
            });
            for (Map.Entry e : list) {
                sb.append(e.getKey() + " " + goodsPrice.get(e.getKey()) + " " + goods.get(
                        e.getKey()) + " \n");
            }


        } else if (option.equals("1")) {
            sb.append("1 yuan coin number=").append(box.get(1)).append("\n").
                    append("2 yuan coin number=").append(box.get(2)).append("\n").
                    append("5 yuan coin number=").append(box.get(5)).append("\n").
                    append("10 yuan coin number=").append(box.get(10)).append("\n");
        } else {
            return "E010:Parameter error";
        }
        sb.delete(sb.length() - 1, sb.length());
        return sb.toString();
    }

    //计算所有商品的剩余数量
    public static int sumGoods() {
        int sum = 0;
        for (int item : goods.values()) {
            sum += item;
        }
        return sum;
    }
}