对最近接近期末的题目集做后的总结性Blog

本文主要是介绍对最近接近期末的题目集做后的总结性Blog，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

一、前言

　　由于接近期末，我们学习的知识也已经差不多全部完结了，所以我在此对整个学期的知识与pta最后三次作业的知识进行总结。总的来说，后三次作业集是集大成之作，无论是题目难度还是题目量都相较之前都有很大的提高，特别是有关电话计费问题的题目，无论是对我们的编程能力还是结构设计能力都有很大的提高，只不过哦。如果老师还是这样接下去教我们的话，未来会变成什么我不知道，我只知道我在这个学期中所有的知识都是由我自己学来的，和老师好不好，和是不是省级一流课程，和这个学校，和这个学科是不是很高级没有半毛钱关系，都是我自己学来的，所以我觉得这样就可以了。

二、设计与分析

1、题目集08：

　　总体上来说这是电信计费的起点，所以在类的设计上需要非常小心，不过总的来说为了遵守程序的简洁设计原则，每个类中的属性和方法都不会太多，总的来说都遵守以下的设计，以下是这个题目集乃至之后题目集的总类图：

　　以下是其中的一些代码（因为实在是太多了）：

class UserRecords{
    ArrayList<CallRecord> CallingInCityRecords = new ArrayList<CallRecord>();
    ArrayList<CallRecord> CallingInProvinceRecords = new ArrayList<CallRecord>();
    ArrayList<CallRecord> CallingInLandRecords = new ArrayList<CallRecord>();
    
    public void addCallingInCityRecords(CallRecord callRecord) {
        CallingInCityRecords.add(callRecord);
    }
    public void addCallingInProvinceRecords(CallRecord callRecord) {
        CallingInProvinceRecords.add(callRecord);
    }
    public void addCallingInLandRecords(CallRecord callRecord) {
        CallingInLandRecords.add(callRecord);
    }
    public ArrayList<CallRecord> getCallingInCityRecords() {
        return CallingInCityRecords;
    }
    public void setCallingInCityRecords(ArrayList<CallRecord> callingInCityRecords) {
        CallingInCityRecords = callingInCityRecords;
    }
    public ArrayList<CallRecord> getCallingInProvinceRecords() {
        return CallingInProvinceRecords;
    }
    public void setCallingInProvinceRecords(ArrayList<CallRecord> callingInProvinceRecords) {
        CallingInProvinceRecords = callingInProvinceRecords;
    }
    public ArrayList<CallRecord> getCallingInLandRecords() {
        return CallingInLandRecords;
    }
    public void setCallingInLandRecords(ArrayList<CallRecord> callingInLandRecords) {
        CallingInLandRecords = callingInLandRecords;
    }
    
}

　　以上的是userrecord类的代码，其中利用了链表的泛型存储各个对象的所有信息。其中大部分类之间的联系是抽象继承。以下是计算在不同区域的电信计费方式的不同类之间的计算。类图和代码如下：

abstract class ChargeRule{
    public abstract double CalCost(ArrayList<CallRecord> callRecords) ;
}
abstract class CallChargeRule extends ChargeRule{
    public double CalCost(ArrayList<CallRecord> callRecords) {
        return 0;
    }
}
class LandPhoneInCityRule extends CallChargeRule{
    @Override    
    public double CalCost(ArrayList<CallRecord> callRecords) {
        double  t = 0;
        for(CallRecord a : callRecords) {
            double t1 = a.getStartTime().getTime();
            double t2 = a.getEndTime().getTime();
            t = t+Math.ceil(((t2-t1)/1000.0/60.0))*0.1;
        }
        return t;
    }              
}
class LandPhoneInLandRule extends CallChargeRule{
    public double CalCost(ArrayList<CallRecord> callRecords) {
        double  t = 0;
        for(CallRecord a : callRecords) {
            double t1 = a.getStartTime().getTime();
            double t2 = a.getEndTime().getTime();
            t = t+Math.ceil(((t2-t1)/1000.0/60.0))*0.6;
        }
        return t;
    }
}
class LandPhoneInProvinceRule extends CallChargeRule{
    public double CalCost(ArrayList<CallRecord> callRecords) {
        double  t = 0;
        for(CallRecord a : callRecords) {
            double t1 = a.getStartTime().getTime();
            double t2 = a.getEndTime().getTime();
            t = t+Math.ceil(((t2-t1)/1000.0/60.0))*0.3;
        }
        return t;
    }
}

　　其中还利用了SimpleDateFormat类的方法，这样在计算两个相隔日期之间的时间时就可以更加准确。

接下来是有关数据的输入与收取问题：

　　所以正则表达式的编写是非常重要的，不仅在这个题目集在后面两个题目集中也是必须的。题目集08的要求是以下代码的解释：（正则表达式太长，只有后面的部分）

TreeMap<String,User> treeMap = new TreeMap<String,User>();
        while(!a.equals("end")) {
            String[] s1 = a.split(" ");
            if(a.matches(b)) {
                String s2 = s1[0].substring(6);
                ChargeMode chargeMode = new LandlinePhoneCharging();                    
                User user=new User(s2,chargeMode);
                treeMap.put(s2,user);                
            }
            if(a.matches(c))
            {
                String[] e = a.split("-");                        
                String[] f = e[1].split(" ");
                String s3 = s1[0].substring(2,6);
                String s4 = s1[1].substring(0,4);
                String s5 = f[0].substring(4);
                
                String time1 = s1[2]+" "+s1[3];
                String time2 = s1[4]+" "+s1[5];
                String q = "079[0-9]|0701";
                Date starttime = new Date();
                Date endtime = new Date();
                SimpleDateFormat sdf3 = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");
                if(treeMap.get(s5)!=null){
                    try {
                        starttime = sdf3.parse(time1);//把特点的字符串转成Date的对象
                    } 
                    catch (ParseException e2) {
                        e2.printStackTrace();
                    }
                    try {
                        endtime = sdf3.parse(time2);
                    } 
                    catch (ParseException e1) {
                        e1.printStackTrace();
                    }    
                    CallRecord cal = new CallRecord(starttime,endtime,s3,s4);
                    if(s4.equals(s3)) {
                        treeMap.get(s5).getUserRecords().addCallingInCityRecords(cal);
                    }
                    else if(s4.matches(q)) {
                        treeMap.get(s5).getUserRecords().addCallingInProvinceRecords(cal);
                    }
                    else {
                        treeMap.get(s5).getUserRecords().addCallingInLandRecords(cal);
                    }
                }    
            }
            a = in.nextLine();
        }
        for(User user:treeMap.values()) {
            System.out.println("0791"+user.getNumber()+" "+user.calCost()+" "+user.calBalance());
        }

　　这就是数据的录入，计算的部分都由后面的类进行。

2、题目集09

　　不同之处其实只是多加了几个继承的类：

class AnswerPhone extends CallChargeRule{

    @Override
    public double CalCost(ArrayList<CallRecord> callRecords) {    
        
        double s = 0;
        for(CallRecord a : callRecords) {                                                       
            s = s + 0.3*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);                
            }
        return s;
    }        
}

 class CellPhoneCity extends CallChargeRule{

    @Override
    public double CalCost(ArrayList<CallRecord> callRecords) {
        // TODO 自动生成的方法存根
                            
        double  s = 0;
        for(CallRecord a : callRecords) {
            if(a.getCallingAddressAreaCode().equals("0791")) {                            
            s = s + 0.1*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            if(a.getCallingAddressAreaCode().matches("079[2-9]|0701|0790")) {                            
                s = s + 0.3*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            else if(!a.getCallingAddressAreaCode().equals("0791")&&!a.getCallingAddressAreaCode().matches("079[0-9]|0701")){                            
                s = s + 0.6*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                    }
        }
        return s;        
    
    }
}
 class CellPhoneLand extends CallChargeRule{

    @Override
    public double CalCost(ArrayList<CallRecord> callRecords) {
        // TODO 自动生成的方法存根
        double  s = 0;
        for(CallRecord a : callRecords) {
            if(a.getCallingAddressAreaCode().equals("0791")) {                            
                s = s + 0.3*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            if(a.getCallingAddressAreaCode().matches("079[2-9]|0701|0790")) {                            
                s = s + 0.3*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            else if(!a.getCallingAddressAreaCode().equals("0791")&&!a.getCallingAddressAreaCode().matches("079[0-9]|0701")){
                s = s + 0.6*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
            }
        }
                
        return s;        
    }
}
 class CellPhoneProvince extends CallChargeRule{

    @Override
    public double CalCost(ArrayList<CallRecord> callRecords) {
        // TODO 自动生成的方法存根
        double  s = 0;
        for(CallRecord a : callRecords) {
            if(a.getCallingAddressAreaCode().equals("0791")) {                            
            s = s + 0.2*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            if(a.getCallingAddressAreaCode().matches("079[2-9]|0701|0790")) {                            
                s = s + 0.3*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                }
            else if(!a.getCallingAddressAreaCode().equals("0791")&&!a.getCallingAddressAreaCode().matches("079[0-9]|0701")){                            
                s = s + 0.6*Math.ceil((a.getEndTime().getTime()-a.getStartTime().getTime())/1000.0/60.0);
                    }
        }
        return s;        
            
    }
}

　　　然后就是数据之间的输入与计算：

TreeMap<String,User> treeMap = new TreeMap<String,User>();
        while(!a.equals("end")) {
            String[] s1 = a.split(" ");
            if(a.matches(b)) {
                String[] c = a.split("-");
                String[] d = c[1].split(" ");
                
                ChargeMode chargeMode = new LandlinePhoneCharging();                    
                User user=new User(d[0],chargeMode);
                
                treeMap.put(d[0],user);            
            }
            if(a.matches(b1)) {
                String[] e = a.split("-");                        
                String[] f = e[1].split(" ");
                ChargeMode chargeMode = new CellPhoneCharging();                    
                User user=new User(f[0],chargeMode);
                treeMap.put(f[0],user);                
            }
            if(a.matches(s3)){        //zj zj            
                String[] e = a.split("-");                        
                String[] f = e[1].split(" ");
                
                
                String stime=f[2]+" "+f[3];
                String etime=f[4]+" "+f[5];
                Date starttime = new Date();
                Date endtime = new Date();
                                                                        
                SimpleDateFormat sdf3 = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");                                        
                try {
                    starttime = sdf3.parse(stime);
                } catch (ParseException e2) {
                    
                    e2.printStackTrace();
                }
                try {
                    endtime = sdf3.parse(etime);
                } catch (ParseException e1) {
                    
                    e1.printStackTrace();
                }                                            
                CallRecord cal = new CallRecord(starttime,endtime,f[0].substring(0, 4),f[1].substring(0, 4));
                if(treeMap.get(f[0])!=null&&treeMap.size()!=0){
                    
                
                if(f[1].substring(0, 4).equals("0791")) {
                    if(treeMap.get(f[0])!=null){
                    treeMap.get(f[0]).getUserRecords().addCallingInCityRecords(cal);}
                    
                    
            }                    
                else if(f[1].substring(0,4).matches(q)) {
                    if(treeMap.get(f[0])!=null){
                    treeMap.get(f[0]).getUserRecords().addCallingInProvinceRecords(cal);}
                    
            }
                else {
                    if(treeMap.get(f[0])!=null){
                    treeMap.get(f[0]).getUserRecords().addCallingInLandRecords(cal);}
                    
            }        }            
        }
             
             if(a.matches(s4)){    //zj sj        
                    String[] e = a.split("-");                        
                    String[] f = e[1].split(" ");
                    
                    
                    String stime=f[3]+" "+f[4];
                    String etime=f[5]+" "+f[6];
                    Date starttime = new Date();
                    Date endtime = new Date();
                                                                            
                    SimpleDateFormat sdf3 = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss");                                        
                    try {
                        starttime = sdf3.parse(stime);
                    } catch (ParseException e2) {
                        
                        e2.printStackTrace();
                    }
                    try {
                        endtime = sdf3.parse(etime);
                    } catch (ParseException e1) {
                        
                        e1.printStackTrace();
                    }                                            
                    CallRecord cal = new CallRecord(starttime,endtime,f[0].substring(0, 4),f[2]);
                    
                    if(treeMap.get(f[0])!=null&&treeMap.size()!=0){
                        
                    
                    if(f[2].equals("0791")) {
                        if(treeMap.get(f[0])!=null){
                        treeMap.get(f[0]).getUserRecords().addCallingInCityRecords(cal);}
                        
                }                    
                    else if(f[2].matches(q)) {
                        if(treeMap.get(f[0])!=null){
                        treeMap.get(f[0]).getUserRecords().addCallingInProvinceRecords(cal);}
                        
                }
                    else {
                        if(treeMap.get(f[0])!=null){
                            
                        treeMap.get(f[0]).getUserRecords().addCallingInLandRecords(cal);
                        }
                        if(treeMap.get(f[1])!=null){  
                            
                        treeMap.get(f[1]).getUserRecords().addAnswerInLandRecords(cal);
                }                            
            }        
        }            
    }

3、题目集10

　　这次题目与其它题目不同之处在于要计算字符的个数，并以此为基础计算费用：

public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner in = new Scanner(System.in);
        String a = in.nextLine();
        String s111 = "u-1\\d{10}\\s3";                
        String s21 = "m-1\\d{10}\\s1\\d{10}\\s([a-z]|[A-Z]|[0-9]|[,]|[.]|[ ]){1,}";
        
        TreeMap<String,User> treeMap = new TreeMap<String,User>();
        while(!a.equals("end")) {
            String[] s1 = a.split(" ");
            if(a.matches(s111)) {
                String[] e = a.split("-");                        
                String[] f = e[1].split(" ");                
                User user=new User(f[0],new MessageCharing());
                treeMap.put(f[0],user);                
            }
            if(a.matches(s21))
            {
                String[] e = a.split("-");                        
                String[] f = e[1].split(" ");
                String s11 = s1[2];        
                MessageRecord mes = new MessageRecord(s11);
                if(treeMap.get(f[0])!=null){
                    treeMap.get(f[0]).getUserRecords().addSendMessageRecords(mes);
                }    
            }
            a = in.nextLine();
        }
        for(User user:treeMap.values()) {
            System.out.print(user.getNumber()+" ");
            System.out.printf("%.1f %.1f\n",user.calCost(),user.calBalance());    
        }    
        
    }
}

abstract class ChargeMode  {
    ArrayList<ChargeRule>  chargeRules = new ArrayList<>();

    public ArrayList<ChargeRule> getChargeRules() {
        return chargeRules;
    }

    public void setChargeRules(ArrayList<ChargeRule> chargeRules) {
        this.chargeRules = chargeRules;
    }
    
    public double calCost(UserRecords userRecords) {
        return 0;
        
    }        
        
}
abstract class ChargeRule {
    public abstract double calCost(ArrayList<MessageRecord> sendMessageRecords);            
}
abstract class CommunicationRecord {
        protected String callingNumber;
        protected String answeringNumber;
        
        
        public String getCallingNumber() {
            return callingNumber;
        }
        public void setCallingNumber(String callingNumber) {
            this.callingNumber = callingNumber;
        }
        public String getAnsweringNumber() {
            return answeringNumber;
        }
        public void setAnsweringNumber(String answeringNumber) {
            this.answeringNumber = answeringNumber;
        }
        
}
abstract class MessageChargeRule extends ChargeRule{

    public double calCost(UserRecords userRecords) {
        // TODO 自动生成的方法存根
        return 0;
    }

}
class MessageCharing extends ChargeMode {
    public double calCost(UserRecords userRecords) {
    
        getChargeRules().add(new SendMessageRule());
        double abs =0;                                                    
        double a =  super.getChargeRules().get(0).calCost(userRecords.getSendMessageRecords());

        abs = a+abs;
        return abs;
    }
}
class MessageRecord extends CommunicationRecord{
    private String message;

    public String getMessage() {
        return message;
    }
    
    public void setMessage(String message) {
        this.message = message;
    }

    public MessageRecord(String message) {
        super();
        this.message = message;
    }
    
}
    
class SendMessageRule extends ChargeRule{
        
        @Override
        public double calCost(ArrayList<MessageRecord> sendMessageRecords) {
            // TODO 自动生成的方法存根
            int sum = 0;
            for(MessageRecord b: sendMessageRecords) {    
                sum += (int)(Math.ceil(b.getMessage().length()/10.0));
                
                     
            }
            if(sum<=3)
                return sum*0.1;    
            else if(sum<=5)
                return 0.3+(sum-3)*0.2;    
            else 
                return 0.7+(sum-5)*0.3;        
        }    
                                
}
class User{
    UserRecords  userRecords = new UserRecords();
    private double balance = 100 ;
    ChargeMode chargemode;
    private String number;
    
    public User(String number, ChargeMode chargemode) {
        // TODO 自动生成的构造函数存根
        this.chargemode=chargemode;
        this.number=number;
    }
    public double getBalance() {
        return balance ;
    }                        
    public UserRecords getUserRecords() {
        return userRecords;
    }
    public void setUserRecords(UserRecords userRecords) {
        this.userRecords = userRecords;
    }                
                                    
    public double calBalance() {
                            
        return balance-chargemode.calCost(userRecords);
    }
    public double calCost() {
        return chargemode.calCost(userRecords);
    }

    public ChargeMode getChargemode() {
        return chargemode;
    }
    public void setChargemode(ChargeMode chargemode) {
        this.chargemode = chargemode;
    }
    public String getNumber() {
        return number;
    }
    public void setNumber(String number) {
        this.number = number;
    }
    
}
class UserRecords{
    
    
    ArrayList<MessageRecord> sendMessageRecords = new ArrayList<MessageRecord>();
    ArrayList<MessageRecord>   receiveMessageRecords= new     ArrayList<MessageRecord>();
    public ArrayList<MessageRecord> getSendMessageRecords() {
        return sendMessageRecords;
    }
    public void setSendMessageRecords(ArrayList<MessageRecord> sendMessageRecords) {
        sendMessageRecords = sendMessageRecords;
    }
    public ArrayList<MessageRecord> getReceiveMessageRecords() {
        return receiveMessageRecords;
    }
    public void setReceiveMessageRecords(ArrayList<MessageRecord> receiveMessageRecords) {
        this.receiveMessageRecords = receiveMessageRecords;
    }
    public void addSendMessageRecords(MessageRecord sendMessageRecord) {
        sendMessageRecords.add(sendMessageRecord);    
    }
public void addReceiveMessageRecords(MessageRecord receiveMessageRecord) {
        receiveMessageRecords.add(receiveMessageRecord);    
    }    
    
}

三、踩坑心得

　　就拿题目集10的后两个题目来说：要注意内部类与外部类之间的联系，特别是内部类方法的应用要注意。

public class Main {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int n = input.nextInt();
        Shop myshop = new Shop(n);
        Shop.InnerCoupons in = myshop.new InnerCoupons(50);
        in.setValue(50);
        in.buy();
        in.setValue(100);
        in.buy();
    }
}

class Shop {
    private int milkCount;
    InnerCoupons coupons50;
    InnerCoupons coupons100;
    public Shop(int milkCount) {
        super();
        this.milkCount = milkCount;
    }
    public int getMilkCount() {
        return milkCount;
    }
    public void setMilkCount(int milkCount) {
        this.milkCount = milkCount;
    }

    class InnerCoupons{
        public int value;

        public InnerCoupons(int value) {
            super();
            this.value = value;
        }
        public int getValue() {
            return value;
        }
        public void setValue(int value) {
            this.value = value;
        }
        public void buy() {
            System.out.println("使用了面值为"+value+"的购物券进行支付");
            int t = Shop.this.getMilkCount();
            t = Shop.this.getMilkCount()-value/50;
            Shop.this.setMilkCount(t);
            System.out.println("牛奶还剩"+t+"箱");
        }
        
    }
}

　　这个即是抽象类的联系

public class Main {
  public static void main(String[] args) {        
       Cat cat = new Cat();
       Dog dog = new Dog();        
      Goat goat = new Goat();
       speak(cat);
       speak(dog);
       speak(goat);
  }
  //定义静态方法speak()
  public static void speak(Animal animal) {
      System.out.println(animal.getAnimalClass()+"的叫声："+animal.shout());
  }

}

//定义抽象类Animal
abstract class Animal{
    public String getAnimalClass() {
        return "";
    }
    public String shout() {
        return "";
    }
}
//基于Animal类，定义猫类Cat，并重写两个抽象方法
class Cat extends Animal{
    public String getAnimalClass() {
        return "猫";
    }
    public String shout() {
        return "喵喵";
    }
}
//基于Animal类，定义狗类Dog，并重写两个抽象方法
class Dog extends Animal{
    public String getAnimalClass() {
        return "狗";
        
    }
    public String shout() {
        return "汪汪";
    }
}
//基于Animal类，定义山羊类Goat，并重写两个抽象方法
class Goat extends Animal{
    public String getAnimalClass() {
        return "山羊";
    }
    public String shout() {
        return "咩咩";
    }
}

四、改进建议

　　我发现在题目08的地方可以把输出改成更加方便的输出：

for(User user:treeMap.values()) {
            System.out.println("0791"+user.getNumber()+" "+user.calCost()+" "+user.calBalance());
        }

改为：

for(User user:treeMap.values()) {
            System.out.println(user.getNumber()+" "+user.calCost()+" "+user.calBalance());
        }

　　这是我发现可以改进的地方。

五、总结

　　在这个12-15周之间我经历了很多困难和失望，无论是对自己还是这个我待的地方，究竟是哪个地方出现了错误，不过现在这些都不用太过在意，我已经理解了我自己的能力究竟能做到多少，不是因为其它人就是我自己没有学好这门课，我想说的就这么多。

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人工智能

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大数据/云计算

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软件/开发工具使用

资讯