题解 | #自动售货系统#
自动售货系统
https://www.nowcoder.com/practice/cd82dc8a4727404ca5d32fcb487c50bf
import java.util.Scanner;
import java.util.HashMap;
// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
private static HashMap<String, Integer> goods = new
HashMap<String, Integer>();//商品A1-A6的数量
private static HashMap<String, Integer> prices = new
HashMap<String, Integer>();//商品A1-A6的价格
private static HashMap<Integer, Integer> coins = new
HashMap<Integer, Integer>();//存钱盒中各面额钱币（1元、2元、5元、10元）的数量
private static Integer change_balance = 0;//零钱余额
private static Integer user_balance = 0;//投币余额
private static Integer goods_count = 0;//商品数量
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
// 注意 hasNext 和 hasNextLine 的区别
while (in.hasNext()) { // 注意 while 处理多个 case
String nextLine = in.nextLine();
String[] orders = nextLine.split(";");
for (int i = 0; i < orders.length; i++) {
String order = orders[i].substring(0, 1);
switch (order) {
case "r" :
init(orders[i]);
break;//系统初始化
case "p" :
System.out.println(coinsIn(orders[i]));
break;//投币
case "b" :
System.out.println(purchase(orders[i]));
break;//购买
case "c" :
coinsOut();
break;//退币
case "q" :
query(orders[i]);
break;//查询
default :
return;
}
}
}
}
/**
* 系统初始化
* @param initialParam
*/
public static void init(String initialParam) {
String[] params = initialParam.split(" ");
System.out.println(OutPut.S001.getDesc());
String[] nums1 = params[1].split("-");
goods.put("A1", Integer.parseInt(nums1[0]));
goods.put("A2", Integer.parseInt(nums1[1]));
goods.put("A3", Integer.parseInt(nums1[2]));
goods.put("A4", Integer.parseInt(nums1[3]));
goods.put("A5", Integer.parseInt(nums1[4]));
goods.put("A6", Integer.parseInt(nums1[5]));
prices.put("A1", 2);
prices.put("A2", 3);
prices.put("A3", 4);
prices.put("A4", 5);
prices.put("A5", 8);
prices.put("A6", 6);
String[] nums2 = params[2].split("-");
coins.put(1, Integer.parseInt(nums2[0]));
coins.put(2, Integer.parseInt(nums2[1]));
coins.put(5, Integer.parseInt(nums2[2]));
coins.put(10, Integer.parseInt(nums2[3]));
goods_count = goods.entrySet().stream().mapToInt(e ->
e.getValue()).sum();//计算商品总数
change_balance = 1 * coins.get(1) + 2 * coins.get(2);//零钱余额
}
/**
* 投币
* @param order 投币指令
*/
public static String coinsIn(String order) {
String amount = order.substring(order.indexOf(" ") + 1);
if ("" != amount && amount.length() > 0) {
int mi = Integer.parseInt(amount);
if (mi == 5 || mi == 10) {
if (mi > change_balance) {
// 零钱不足，无法找零，不能投币
return OutPut.E003.getDesc();
} else if (goods_count == 0) {
// 商品售罄，投币失败
return OutPut.E005.getDesc();
} else {
// 投币成功，钱币数量+1
coins.put(mi, coins.get(mi) + 1);
}
} else if (mi == 1 || mi == 2) {
if (goods_count == 0) {
// 商品全部售罄，投币失败
return OutPut.E005.getDesc();
} else {
change_balance += mi;//计入零钱余额
coins.put(mi, coins.get(mi) + 1);//投币成功，钱币数量+1
}
} else {
// 无效的面额
return OutPut.E002.getDesc();
}
user_balance += mi;//投币成功，计入用户投币余额
return OutPut.S002.getDesc() + user_balance;
}
return OutPut.E002.getDesc();
}
/**
* 退币
*/
public static void coinsOut() {
int last = user_balance;//剩余未退余额
if (last == 0) {
//投币余额为0
System.out.println(OutPut.E009.getDesc());
} else {
int one = 0, two = 0, five = 0, ten = 0;//四种面值退的张数
while (last > 0) {
int temp = last / 10;//若要最少总张数，从最大面值开始退起，当前面值最多应退的张数，实际退的张数要取决于存钱盒里存有的张数
while (coins.get(10) > 0 && temp > 0) {
ten++;
temp--;
last -= 10;
coins.put(10, coins.get(10) - 1);
}
temp = last / 5;
while (coins.get(5) > 0 && temp > 0) {
five++;
temp--;
last -= 5;
coins.put(5, coins.get(5) - 1);
}
temp = last / 2;
while (coins.get(2) > 0 && temp > 0) {
two++;
temp--;
last -= 2;
change_balance -= 2;
coins.put(2, coins.get(2) - 1);
}
temp = last;
while (coins.get(1) > 0 && temp > 0) {
one++;
temp--;
last -= 1;
change_balance--;
coins.put(1, coins.get(1) - 1);
}
}
System.out.println("1 yuan coin number=" + one);
System.out.println("2 yuan coin number=" + two);
System.out.println("5 yuan coin number=" + five);
System.out.println("10 yuan coin number=" + ten);
user_balance = 0;//找零结束，余额清零
}
}
/**
* 购买商品
* @param order 购买指令
*/
public static String purchase(String order) {
String goodsName = order.substring(order.indexOf(" ") + 1);
if (goods.containsKey(goodsName)) {
if (goods.get(goodsName) == 0) {
// 商品售罄
return OutPut.E007.getDesc();
} else if (prices.get(goodsName) > user_balance) {
// 余额不足，购买失败
return OutPut.E008.getDesc();
} else {
user_balance -= prices.get(goodsName);// 购买成功，投币余额扣减
return OutPut.S003.getDesc() + user_balance;
}
} else {
// 商品不存在
return OutPut.E006.getDesc();
}
}
/**
* 查询
* @param order 查询指令
*/
public static void query(String order) {
if (order.contains(" ") && order.length() == 3) {
String type = order.substring(2);
if ("0".equals(type)) {
//查询商品信息
goods.entrySet().forEach(e ->
System.out.println(e.getKey() + " " + prices.get(e.getKey()) + " " +
e.getValue()));
} else if ("1".equals(type)) {
//查询存钱盒信息
coins.entrySet().forEach(e ->
System.out.println(e.getKey() + " yuan coin number=" + e.getValue()));
} else {
System.out.println(OutPut.E010.getDesc());
}
} else {
System.out.println(OutPut.E010.getDesc());
}
}
}
/**
*返回状态码 常量
*/
enum OutPut {
S001(":Initialization is successful"),
S002(":Pay success,balance="),
S003(":Buy success,balance="),
E002(":Denomination error"),
E003(":Change is not enough, pay fail"),
E005(":All the goods sold out"),
E006(":Goods does not exist"),
E007(":The goods sold out"),
E008(":Lack of balance"),
E009(":Work failure"),
E010(":Parameter error");
private String desc;
private OutPut(String desc) {
this.desc = desc;
}
public String getDesc() {
return name() + desc;
}
}
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