20165235 第十周课下补做

20165235 祁瑛 第十周课下补做

相关知识点的总结

LinkedList<String> mylist=new LinkedList<String>()来创建一个链表。
mylist.add（）;来添加结点。
get（int index）来获取链表中第index个位置的结点的对象。
public static sort（List<E>）将链表中的元素升序排列
public static binarySearch（List<T>,T key,CompareTo<T>c):使用折半查找list中的数据Key；
实现Comparable接口要重写compareTo方法。Collections类中的sort方法是面向Comparable接口设计的。

课上内容的补做，结果截图

数据结构-排序

import java.util.*;
public class Example {
    public  static void main(String[] args) {
        List<Student> list = new LinkedList<>();
        list.add(new Student(20165233,"张雨昕",99,91,89));
        list.add(new Student(20165234,"刘京甫",76,66,95));
        list.add(new Student(20165235,"祁 瑛",77,81,68));
        list.add(new Student(20165236,"郭金涛",89,45,66));
        list.add(new Student(20165237,"方若鸿",82,80,86));
        SortTotal_score sortBytotal_score = new SortTotal_score();
        Collections.sort(list, sortBytotal_score);
        SortID sortByID = new SortID();
        Collections.sort(list, sortByID);
        System.out.println("学号排序：");
        for (Student student : list) {
            System.out.println(student);
        }
        Collections.sort(list, sortBytotal_score);
        System.out.println("成绩排序：");
        for (Student student : list) {
            System.out.println(student);
        }
    }
}
class Student {
    private int id;//表示学号
    private String name;//表示姓名
    private int age;//表示年龄
    private String sex;
    private double computer_score;//表示计算机课程的成绩
    private double english_score;//表示英语课的成绩
    private double maths_score;//表示数学课的成绩
    private double total_score;// 表示总成绩
    private double ave_score; //表示平均成绩
    @Override
    public String toString() {
        return " "+name+" "+id+" "+total_score;
    }
    public Student(int id, String name,double computer_score,
                   double english_score,double maths_score) {
        this.id = id;
        this.name = name;
        this.computer_score = computer_score;
        this.english_score = english_score;
        this.maths_score = maths_score;
    }
    public int getId() {
        return id;
    }//获得当前对象的学号，
    public double getComputer_score() {
        return computer_score;
    }//获得当前对象的计算机课程成绩,
    public double getMaths_score() {
        return maths_score;
    }//获得当前对象的数学课程成绩,
    public double getEnglish_score() {
        return english_score;
    }//获得当前对象的英语课程成绩,
    public void setId(int id) {
        this.id = id;
    }// 设置当前对象的id值,
    public void setComputer_score(double computer_score) {
        this.computer_score = computer_score;
    }//设置当前对象的Computer_score值,
    public void setEnglish_score(double english_score) {
        this.english_score = english_score;
    }//设置当前对象的English_score值,
    public void setMaths_score(double maths_score) {
        this.maths_score = maths_score;
    }//设置当前对象的Maths_score值,
    public double getTotalScore() {
        total_score=computer_score + maths_score + english_score;
        return total_score;
    }// 计算Computer_score, Maths_score 和English_score 三门课的总成绩。
    public double getAveScore() {
        return getTotalScore() / 3;
    }// 计算Computer_score, Maths_score 和English_score 三门课的平均成绩。
}
class SortID implements Comparator<Student> {
    @Override
    public int compare(Student a, Student b) {
        return a.getId() - b.getId();
    }
}
class SortTotal_score implements Comparator<Student> {
    @Override
    public int compare(Student a, Student b) {
        return (int)( a.getTotalScore() - b.getTotalScore());
    }
}

• 码云链接

数据结构单链表

import java.util.*;
public class Mylist {
    public static void main(String [] args) {
        //选用合适的构造方法，用你学号前后各两名同学的学号创建四个结点
        Node<String> node1 =new Node<String>("20165233",null);
        Node<String> node2 =new Node<String>("20165234",null);
        Node<String> node3 =new Node<String>("20165236",null);
        Node<String> node4 =new Node<String>("20165237",null);
        //把上面四个节点连成一个没有头结点的单链表
        node1.next=node2;
        node2.next=node3;
        node3.next=node4;
        node4.next=node1;
        //遍历单链表，打印每个结点的
        Node<String> node =node1 ;
        System.out.println("打印插入前的链表数据");
        for (int i=0;i<4;i++) {
            System.out.println(node.data.toString());
            node = node.next;
        }
        //把你自己插入到合适的位置（学号升序）
        //遍历单链表，打印每个结点的
        System.out.println("打印插入后的链表数据");
        node=node1;
        Node<String> s=new Node<String>("20165235",null);
        for(int i=0;i<5;i++){
            System.out.println(node.data.toString());
            node = node.next;
           if(node==node2){
               node2.next=s;
               s.next=node3;
           }
        }
        //从链表中删除自己
        node=node1;
        for(int i=0;i<4;i++){
            node = node.next;
            if(node==s){
                s=null;
                node2.next=node3;
                node3.next=node4;
            }
        }
       node =node1 ;
        System.out.println("打印删除后的链表数据");
        for (int i=0;i<4;i++) {
            System.out.println(node.data.toString());
            node = node.next;
        }

    }
}
class Node<String>                             //单链表结点类，T指定结点的元素类型
{
    public String data;                               //数据域，存储数据元素
    public Node<String> next;                         //地址域，引用后继结点

    public Node(String data, Node<String> next)            //构造结点，data指定数据元素，next指定后继结点
    {
        this.data = data;                        //T对象引用赋值
        this.next = next;                        //Node<T>对象引用赋值
    }
    public Node()
    {
        this(null, null);
    }
    @Override
    public java.lang.String toString()                     //返回结点数据域的描述字符串
    {
        return this.data.toString();
    }
}

• 码云链接

教材第十五章的代码分析

import java.util.*;
public class Example15_2 {
   public static void main(String args[]){
      List<String> list=new LinkedList<String>();//建立一个String类型的链表
      for(int i=0;i<=60096;i++){
             list.add("speed"+i);//对链表插入节点
      }
      Iterator<String> iter=list.iterator();//用iterator()方法获得一个Iterator对象
      long starttime=System.currentTimeMillis();
      while(iter.hasNext()){//当链表中还有数据时返回true
           String te=iter.next();//te指向下一个节点
      }
      long endTime=System.currentTimeMillis();
      long result=endTime-starttime;
      System.out.println("使用迭代器遍历集合所用时间:"+result+"毫秒");
      starttime=System.currentTimeMillis();
      for(int i=0;i<list.size();i++){
          String te=list.get(i);
      }
      endTime=System.currentTimeMillis();
      result=endTime-starttime;
      System.out.println("使用get方法遍历集合所用时间:"+result+"毫秒");
    }
}

import java.util.*;
public class Example15_3 {
    public static void main(String args[]){
        LinkedList mylist=new LinkedList();//建立链表
        mylist.add("你");                 //链表中的第一个节点
        mylist.add("好");                 //链表中的第二个节点
        int number=mylist.size();         //获取链表的长度
        for(int i=0;i<number;i++){
          String temp=(String)mylist.get(i); //必须强制转换取出的数据
          System.out.println("第"+i+"节点中的数据:"+temp);
        } 
        Iterator iter=mylist.iterator();
        while(iter.hasNext()) {
          String te=(String)iter.next();  //必须强制转换取出的数据
          System.out.println(te);
        }
   }
}

import java.util.*;
class Student implements Comparable { //实现Comparab接口
   int height=0;
   String name;
   Student(String n,int h) {
      name=n;
      height = h; 
   }
   public int compareTo(Object b) { // 重写接口中的compareTo方法，两个Student对象相等当且仅当二者的height值相等
     Student st=(Student)b;
     return (this.height-st.height);
   }
}
public class Example15_4 {
    public static void main(String args[ ]) { 
       List<Student> list = new LinkedList<Student>();
       list.add(new Student("张三",188));//第一个节点
       list.add(new Student("李四",178));//第二个节点
       list.add(new Student("周五",198)); //的三个接点
       Iterator<Student> iter=list.iterator();
       System.out.println("排序前,链表中的数据");
       while(iter.hasNext()){
          Student stu=iter.next();
          System.out.println(stu.name+ "身高:"+stu.height);
       }//遍历链表
       Collections.sort(list);//使用Collections类的静态方法sort来升序排序
       System.out.println("排序后,链表中的数据");
       iter=list.iterator();
       while(iter.hasNext()){
          Student stu=iter.next();
          System.out.println(stu.name+ "身高:"+stu.height);
       }
       Student zhaoLin = new Student("zhao xiao lin",178);
       int index = Collections.binarySearch(list,zhaoLin,null);//使用Collections中的静态方法binarySearch（）方法进行折半查找
       if(index>=0) {
            System.out.println(zhaoLin.name+"和链表中"+list.get(index).name+"身高相同");
       }
    }
}

import java.util.*;
public class Example15_5 {
    public static void main(String args[ ]) { 
       List<Integer> list = new LinkedList<Integer>//建立一个int类型的链表
       for(int i=10;i<=50;i=i+10)//添加5个节点
           list.add(new Integer(i));
       System.out.println("洗牌前,链表中的数据");
       Iterator<Integer> iter=list.iterator();
       while(iter.hasNext()){
          Integer n=iter.next();
          System.out.printf("%d	",n.intValue());
       }
       Collections.shuffle(list);//将list中的数据重新排列
       System.out.printf("
洗牌后,链表中的数据
");
       iter=list.iterator();
       while(iter.hasNext()){
          Integer n=iter.next();
          System.out.printf("%d	",n.intValue());
       }
       System.out.printf("
再向右旋转1次后,链表中的数据
");
       Collections.rotate(list,1);//翻转list中的数据
       iter=list.iterator();
       while(iter.hasNext()){
          Integer n=iter.next();
          System.out.printf("%d	",n.intValue());
       }
    }
}

`import java.util.*;
public class Example15_6 {
   public static void main(String args[]) {
      Stack<Integer> stack=new Stack<Integer>();//建立一个int类型的堆栈
      stack.push(new Integer(1)); //将1压栈
      stack.push(new Integer(1));//将1压栈，现在栈中两个数
      int k=1;
      while(k<=10) {//求10个斐波那契数
        for(int i=1;i<=2;i++) {
          Integer F1=stack.pop();//弹栈第一个数
          int f1=F1.intValue();
          Integer F2=stack.pop();//弹栈第二个数
          int f2=F2.intValue();
          Integer temp=new Integer(f1+f2);
          System.out.println(""+temp.toString()); 
          stack.push(temp);//两数之和压栈
          stack.push(F2);//第二个数压栈
          k++;
        }
      } 
   }
}

import java.util.*;
class Student implements Comparable {
   int english=0;
   String name;
   Student(int english,String name) {
      this.name=name;
      this.english=english;
   }
   public int compareTo(Object b) {//重写compareTo方法
      Student st=(Student)b;//Object类型强制转化为Student类
      return (this.english-st.english);
   }
}
public class Example15_8 {
  public static void main(String args[]) {
     TreeSet<Student> mytree=new TreeSet<Student>();
     Student st1,st2,st3,st4;
     st1=new Student(90,"赵一");
     st2=new Student(66,"钱二");
     st3=new Student(86,"孙三");
     st4=new Student(76,"李四");
     mytree.add(st1);//添加数集结点
     mytree.add(st2);
     mytree.add(st3);
     mytree.add(st4);
     Iterator<Student> te=mytree.iterator();
     while(te.hasNext()) {//遍历树集结点
        Student stu=te.next();
        System.out.println(""+stu.name+" "+stu.english);
     }
  }
}

import java.util.*;
class StudentKey implements Comparable { 
   double d=0; 
   StudentKey (double d) {
     this.d=d;
   }
   public int compareTo(Object b) {//重写compareTo方法
     StudentKey st=(StudentKey)b;//强制转化为StudentKey类型
     if((this.d-st.d)==0)
        return -1;
     else
        return (int)((this.d-st.d)*1000);
  }
}
class Student { 
    String name=null;
    double math,english;
    Student(String s,double m,double e) {
       name=s; 
       math=m;
       english=e;
    }
}
public class Example15_9 {
   public static void main(String args[ ]) {
      TreeMap<StudentKey,Student>  treemap= new TreeMap<StudentKey,Student>();
      String str[]={"赵一","钱二","孙三","李四"};
      double math[]={89,45,78,76};
      double english[]={67,66,90,56};
      Student student[]=new Student[4];
      for(int k=0;k<student.length;k++) {
         student[k]=new Student(str[k],math[k],english[k]);
      }
      StudentKey key[]=new StudentKey[4] ;
      for(int k=0;k<key.length;k++) {
         key[k]=new StudentKey(student[k].math); //关键字按数学成绩排列大小
      }
      for(int k=0;k<student.length;k++) {
         treemap.put(key[k],student[k]);          
      }
      int number=treemap.size();//获取treemap的元素个数
      System.out.println("树映射中有"+number+"个对象,按数学成绩排序:");
      Collection<Student> collection=treemap.values();//获取数据
      Iterator<Student> iter=collection.iterator();
      while(iter.hasNext()) {
         Student stu=iter.next();
         System.out.println("姓名 "+stu.name+" 数学 "+stu.math);
      }
      treemap.clear();//清空树映射
      for(int k=0;k<key.length;k++) {
         key[k]=new StudentKey(student[k].english);//关键字按英语成绩排列大小
      }
      for(int k=0;k<student.length;k++) {
         treemap.put(key[k],student[k]);
      }
      number=treemap.size();
      System.out.println("树映射中有"+number+"个对象:按英语成绩排序:");
      collection=treemap.values();
      iter=collection.iterator();
      while(iter.hasNext()) {
         Student stu=(Student)iter.next();
         System.out.println("姓名 "+stu.name+" 英语 "+stu.english);
      }
    }
}

补做教材第十五章的编程题目

编程题一

import java.util.*;
public class Series {
    public static void main(String args[]){
        Stack<Integer> stack =new Stack<Integer>();
        Scanner scanner=new Scanner(System.in);
        int n=scanner.nextInt();
        int a1=3;
        int a2=8;
        stack.push(a1);//第一个数压栈
        stack.push(a2);//第二个数压栈
        int temp=0;//计算结果设一个中间变量temp
        for(int i=0;i<n;i++){
            a2=stack.pop();//弹出第二个数
            a1=stack.pop();//弹出第一个数
            temp=2*a2+2*a1;//计算结果
            stack.push(a2);//第二个数压栈
            stack.push(temp);//计算结果压栈
            System.out.println(temp);
        }
    }
}

• 码云链接

编程题二

import java.util.*;
public class SortEnglish {
    public static void main(String args[]) {
        TreeSet<Score> mytree = new TreeSet<>();
        List<Score> mylist = new LinkedList<Score>();
        mylist.add(new Score("赵一", 89));
        mylist.add(new Score("钱二", 99));
        mylist.add(new Score("孙三", 100));
        mylist.add(new Score("李四", 92));
        mylist.add(new Score("周五", 88));
        //添加节点
        Iterator<Score> score = mylist.iterator();
        System.out.println("排序之前的：");
        while (score.hasNext()) {
            Score sco = score.next();
            mytree.add(sco);
            System.out.println(sco.name + " " + sco.english);
        }
        //将链表中的成绩放入树集中
        System.out.println("排序之后的：");
        Iterator<Score> te = mytree.iterator();
        while (te.hasNext()) {
            Score stu = te.next();
            System.out.println("" + stu.name + " " + stu.english);
        }
    }
}

    class Score implements Comparable {
        int english = 0;
        String name = "";

        Score(String name, int english) {
            this.name = name;
            this.english = english;
        }

        @Override
        public int compareTo(Object a) {
            Score b = (Score) a;
            return this.english - b.english;
        }
    }

编程题三

• 码云链接

import java.util.*;
class Sort implements Comparable {
    double d=0;
    Sort (double d) {
        this.d=d;
    }
    @Override
    public int compareTo(Object b) {
        Sort st=(Sort) b;
        if((this.d-st.d)==0) {
            return -1;
        }
        else {
            return (int) ((this.d - st.d) * 1000);
        }
    }
}
class U {
    String name="";
    double speed,capacity;
    U(String name,double speed,double capacity) {
        this.name=name;
        this.capacity=capacity;
        this.speed=speed;
    }
}
public class PriceSort {
    public static void main(String args[ ]) {
        TreeMap<Sort,U>  treemap= new TreeMap<Sort,U>();
        String name[]={"A","B","C","D","E","F","G","H","I","J"};
        double speed[]={111,100,101,345,213,433,565,333,454,454};
        double capacity[]={4,10,32,64,128,34,68,120,112,1024};
        U u[]=new U[10];
        for(int k=0;k<u.length;k++) {
            u[k]=new U(name[k],speed[k],capacity[k]);
        }
        Sort key[]=new Sort[10] ;
        for(int k=0;k<key.length;k++) {
            key[k]=new Sort(u[k].speed);
        }
        for(int k=0;k<u.length;k++) {
            treemap.put(key[k],u[k]);
        }
        System.out.println("按speed排序:");
        Collection<U> collection=treemap.values();
        Iterator<U> iter=collection.iterator();
        while(iter.hasNext()) {
            U stu=iter.next();
            System.out.println("品牌"+stu.name+"speed："+stu.speed);
        }
        treemap.clear();
        for(int k=0;k<key.length;k++) {
            key[k]=new Sort(u[k].capacity);
        }
        for(int k=0;k<u.length;k++) {
            treemap.put(key[k],u[k]);
        }
        System.out.println("按capacity排序:");
        collection=treemap.values();
        iter=collection.iterator();
        while(iter.hasNext()) {
            U stu=(U)iter.next();
            System.out.println("品牌"+stu.name+" capacity ："+stu.capacity);
        }
    }
}

• 码云链接

心得体会

本次测试我没有能够做出排序和单链表的题目，一是考试时间过短，二是对数据结构这块内容学习的不够深。而通过本次课下补做我对数据结构的了解有进了一步。