HUAWEI华为Java软件工程师机试题——集合类
1、有如下Student对象，属性如图所示：
其中classNum表示学生的班级编号，比如：class05
有如下List：
List list = new ArrayList();
list.add(new Student(“Tom”, 18, 100, “class05”));
list.add(new Student(“Jerry”, 22, 70, “class04”));
list.add(new Student(“Owen”, 25, 90, “class05”));
list.add(new Student(“Jim”, 30,80 , “class05”));
list.add(new Student(“Steve”, 28, 66, “class06”));
list.add(new Student(“Kevin”, 24, 100, “class04”));
在这个list 的基础上，完成下列要求：
1） 计算所有学生的平均年龄
2） 计算各个班级的平均分
2、已知有16支足球队参加2008北京奥运会。写一个程序，随机把16支球队分成四组
3、设计Account对象如下：
要求完善设计，使得该Account 对象能够自动分配id。
给定一个List 如下：
List list = new ArrayList();
list.add(new Account(10.00, “1234”));
list.add(new Account(15.00, “5678”));
list.add(new Account(0, “1010”));
要求把List 中的内容放到一个Map 中，该Map 的键为id，值为相应的Account 对象。
最后遍历这个Map，打印所有Account 对象的id 和余额。
4、已知某学校课程安排如下：
完成下列要求：
1） 使用一个Map，以老师的名字作为键，以老师教授的课程名作为值，表示上述
课程安排。
2） 增加了一位新老师Allen 教JDBC
3） Lucy 改为教CoreJava
4） 遍历Map，输出所有的老师及老师教授的课程
5） *利用Map，输出所有教JSP 的老师。
5、利用Map，完成下面的功能：
从命令行读入一个字符串，表示一个年份，输出该年的世界杯冠军是哪支球队。如果该
年没有举办世界杯，则输出：没有举办世界杯。
6、在上题的基础上继续完成：输入球队的名字，输出得冠的年份
如：输入巴西，输出1958 1962 1970 1994 2002
7、完成下面的要求
1) 创建一个List，在List 中增加三个工人，基本信息如下：
姓名 年龄 工资
zhang3 18 3000
li4 25 3500
wang5 22 3200
2) 在li4 之前插入一个工人，信息为：姓名：zhao6，年龄：24，工资3300
3) 删除wang5 的信息
4) 利用for 循环遍历，打印List 中所有工人的信息
我的答案(HCQ，2018/8/7)
1.
package JulyTwelfthHUAWEI;
public class Student {
private String name;
private int age;
private double score;
private String classNum;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public double getScore() {
return score;
}
public void setScore(double score) {
this.score = score;
}
public String getClassNum() {
return classNum;
}
public void setClassNum(String classNum) {
this.classNum = classNum;
}
public Student(String name, int age, double score, String classNum) {
super();
this.name = name;
this.age = age;
this.score = score;
this.classNum = classNum;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
}
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package JulyTwelfthHUAWEI;
import java.util.List;
import java.util.ArrayList;
public class StudentTest {
public static void main(String[] args) {
List<Student> list = new ArrayList<Student>();
list.add(new Student("Tom", 18, 100, "class05"));
list.add(new Student("Jerry", 22, 70, "class04"));
list.add(new Student("Owen", 25, 90, "class05"));
list.add(new Student("Jim", 30, 80, "class05"));
list.add(new Student("Steve", 28, 66, "class06"));
list.add(new Student("Kevin", 24, 100, "class04"));
double sumAge = 0;
double sumScore4 = 0;
double sumScore5 = 0;
double sumScore6 = 0;
double num4 = 0;
double num5 = 0;
double num6 = 0;
// 1)
for(Student stu : list) {
sumAge+=stu.getAge();
}
System.out.print("所有学生的平均年龄：");
System.out.println(sumAge/6.0);
// 2)
for(int i=0; i<list.size(); i++) {
if(list.get(i).getClassNum().equals("class04")) {
sumScore4+=list.get(i).getScore();
num4++;
}
if(list.get(i).getClassNum().equals("class05")) {
sumScore5+=list.get(i).getScore();
num5++;
}
if(list.get(i).getClassNum().equals("class06")) {
sumScore6+=list.get(i).getScore();
num6++;
}
}
System.out.print("class04的平均分数：");
System.out.println(sumScore4/num4);
System.out.print("class05的平均分数：");
System.out.println(sumScore5/num5);
System.out.print("class06的平均分数：");
System.out.println(sumScore6/num6);
}
}2.
package JulyTwelfthHUAWEI;
import java.util.List;
public class Group {
private int id;
private String name;
private List<String> team;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public List<String> getTeam() {
return team;
}
public void setTeam(List<String> team) {
this.team = team;
}
public Group(int id, String name, List<String> team) {
super();
this.id = id;
this.name = name;
this.team = team;
}
public Group() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Group [id=" + id + ", name=" + name + ", team=" + team + "]";
}
}
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package JulyTwelfthHUAWEI;
import java.util.List;
import java.util.ArrayList;
import java.util.Collections;
public class Football {
public static void main(String[] args) {
List<String> teams = new ArrayList<String>();
Collections.addAll(teams,"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P");
Collections.shuffle(teams);
System.out.println(teams);
Group[] groups = new Group[4];
for(int i = 0; i<groups.length; i++) {
groups[i] = new Group(i, "G"+i, new ArrayList<>());
}
int n = 0;
for(int i = 0;i < teams.size();i++){
groups[n++ % 4].getTeam().add(teams.get(i));
}
for(int i = 0; i<groups.length; i++) {
System.out.println(groups[i].getName()+groups[i].getTeam());
}
}
}3.
package JulyTwelfthHUAWEI;
import java.util.Random;
public class Account {
private long id;
private double balance;
private String password;
Random rd = new Random();
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public double getBalance() {
return balance;
}
public void setBalance(double balance) {
this.balance = balance;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Account(double balance, String password) {
super();
this.id = Math.abs(rd.nextLong());
this.balance = balance;
this.password = password;
}
public Account() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Account [id=" + id + ", balance=" + balance + "]";
}
}
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package JulyTwelfthHUAWEI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class AccountTest {
public static void main(String[] args) {
List<Account> list = new ArrayList<Account>();
list.add(new Account(10.00, "1234"));
list.add(new Account(15.00, "5678"));
list.add(new Account(0, "1010"));
Map<Long, Account> map = new HashMap<>();
for(Account account : list) {
map.put(account.getId(), account);
}
Collection<Account> c = map.values();
for (Account a : c) {
System.out.println(a.toString());
}
}
}4.
package JulyTwelfthHUAWEI;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
public class Teacher {
public static void main(String[] args) {
// 1)
Map<String, String> map = new HashMap<>();
map.put("Tom", "CoreJava");//1001=jack
map.put("John", "Oracle");
map.put("Susan", "Oracle");
map.put("Jerry", "JDBC");
map.put("Kevin", "JSP");
map.put("Lucy", "JSP");
// 2)
map.put("Allen", "JDBC");
// 3)
map.replace("Lucy", "CoreJava");
// 4)
System.out.println(map);
// 5)
Set<Entry<String, String>> set = map.entrySet();
for(Entry<String, String> entry : set) {
if(entry.getValue().equals("JSP")) {
System.out.println(entry.getKey());
}
}
}
}5. and 6.
package JulyTwelfthHUAWEI;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.Set;
public class WorldCup {
private static Scanner sc;
public static void main(String[] args) {
Map<String, String> map = new HashMap<>();
map.put("2006", "意大利");
map.put("2002", "巴西");
map.put("1998", "法国");
map.put("1994", "巴西");
map.put("1990", "德国");
map.put("1986", "阿根廷");
map.put("1982", "意大利");
map.put("1978", "阿根廷");
map.put("1974", "德国");
map.put("1970", "巴西");
map.put("1966", "英格兰");
map.put("1962", "巴西");
map.put("1958", "巴西");
map.put("1954", "德国");
map.put("1950", "乌拉圭");
map.put("1938", "意大利");
map.put("1934", "意大利");
map.put("1930", "乌拉圭");
sc = new Scanner(System.in);
// 5.
System.out.print("请输入年份：");
String year = sc.next();
if(map.containsKey(year)==true) {
System.out.print(year+"年的世界杯冠军是：");
System.out.println(map.get(year));
} else {
System.out.println(year+"年没有举办世界杯。");
}
// 6.
System.out.print("请输入冠军球队的国家：");
String team = sc.next();
Set<Entry<String, String>> set = map.entrySet();
System.out.print(team+"队获得世界杯冠军的年份是：");
for(Entry<String, String> entry : set) {
if(entry.getValue().equals(team)) {
System.out.print(entry.getKey()+" ");
}
}
}
}7.
package JulyTwelfthHUAWEI;
public class Worker {
private String name;
private int age;
private int salary;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
public Worker(String name, int age, int salary) {
super();
this.name = name;
this.age = age;
this.salary = salary;
}
public Worker() {
super();
// TODO Auto-generated constructor stub
}
@Override
public String toString() {
return "Worker [name=" + name + ", age=" + age + ", salary=" + salary + "]";
}
}
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package JulyTwelfthHUAWEI;
import java.util.ArrayList;
import java.util.List;
public class WorkerTest {
public static void main(String[] args) {
// 1)
List<Worker> list = new ArrayList<Worker>();
list.add(new Worker("zhang3", 18, 3000));
list.add(new Worker("li4", 25, 3500));
list.add(new Worker("wang5", 22, 3200));
// 2)
list.add(1, new Worker("zhao6", 24, 3300));
// 3)
for(int i=0; i<list.size(); i++) {
if(list.get(i).getName()=="wang5") {
list.remove(i);
}
}
// 4)
for(int i=0; i<list.size(); i++) {
System.out.println(list.get(i).toString());
}
}
}