前言：
这次博客是对之前发布的6-8次PTA题目集（成绩计算系列）的一次总结，经过前几次系列题目的磨练，相信对于认真写的同学来说这次成绩系列的题目也不是很难。只要肯花点时间，拿个及格不是问题。题量来说还是比较少的，对于一些高手来说，几个小时便可拿到高分。
设计与分析：
7-1 课程成绩统计程序-1
类的设计老师已经大体讲过了，我的设计与老师的稍有不同，我的只有一个成绩类，如果是考核类型的课程，平时分就为0分。这些题目的主要难度就在于排序。排序的方法有好几种，如果使用恰当，可以大大提高程序效率。
这是源代码
import java.text.Collator;
import java.util.*;
import java.util.stream.Collectors;
class Student{
String student_num;
String name;
public Student(String student_num,String name){
this.name=name;
this.student_num=student_num;
}
}
class Course{
String name;
String nature;
String assessment;
public Course(String name,String nature,String assessment){
this.name=name;
this.nature=nature;
this.assessment=assessment;
}
}
class Class{
String num;
ArrayList<Student> studentList=new ArrayList<>();
public Class(String num){
this.num=num;
}
public void Addstudent(Student student){
studentList.add(student);
}
}
class Grade{
int regularscore;
int finalscore;
double totalscore;
public Grade(int regularscore,int finalscore,int totalscore){
this.regularscore=regularscore;
this.finalscore=finalscore;
this.totalscore=totalscore;
}
}
class Matching{
Student student;
Course course;
Grade grade;
public Matching(Student student,Course course,Grade grade){
this.student=student;
this.course=course;
this.grade=grade;
}
}
class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
List<String> commands = new ArrayList<>(); // 存储用户输入的所有指令
HashMap<String, Course> courseMap = new HashMap<>();
List<Class> classList = new ArrayList<>();
List<Matching> matchingList = new ArrayList<>();
while (true) {
String line = input.nextLine();
if (line.equals("end")) {
break;
} else {
commands.add(line); // 将输入存储起来
}
}
input.close();
// 遍历存储的所有指令，并执行相应操作
Set<String> validCourseNatures = new HashSet<>(Arrays.asList("必修", "选修"));
Set<String> validAssessments = new HashSet<>(Arrays.asList("考试", "考察"));
Set<String> studentCoursePairs = new HashSet<>();
for (String command : commands) {
String[] parts = command.split(" ");
if (parts.length >= 4) {
String studentCoursePair = parts[0] + " " + parts[2];
if (studentCoursePairs.contains(studentCoursePair)) {
continue;
} else {
studentCoursePairs.add(studentCoursePair);
}
}
if (command.matches("\\D+\\s\\D+\\s\\D+")&&validAssessments.contains(parts[2])&&validCourseNatures.contains(parts[1])&&parts[0].length() < 10) {
if (parts[1].equals("必修") && parts[2].equals("考察")) {
System.out.println(parts[0] + " : course type & access mode mismatch");
continue;
}else{
if(courseMap.get(parts[0])!=null){
continue;
}else{
Course course = new Course(parts[0], parts[1], parts[2]);
courseMap.put(parts[0], course);
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d+\\s\\d+")&&isValid(Integer.parseInt(parts[4]),Integer.parseInt(parts[3]),parts[0],parts[1])) {
Student student = new Student(parts[0], parts[1]);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2])!=null&&(courseMap.get(parts[2]).nature.equals("必修") || courseMap.get(parts[2]).assessment.equals("考试"))) {
Grade grade = new Grade(Integer.parseInt(parts[3]), Integer.parseInt(parts[4]), (int) (Integer.parseInt(parts[3]) * 0.3 + Integer.parseInt(parts[4]) * 0.7));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if(courseMap.get(parts[2])==null){
System.out.println(parts[2] +" does not exist");
}else{
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d+")&&isValid(0,Integer.parseInt(parts[3]),parts[0],parts[1])) {
Student student = new Student(parts[0], parts[1]);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2])!=null&&courseMap.get(parts[2]).nature.equals("选修")) {
Grade grade = new Grade(0, Integer.parseInt(parts[3]), (int) Integer.parseInt(parts[3]));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if(courseMap.get(parts[2])==null){
System.out.println(parts[2] +" does not exist");
}else{
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
} else {
System.out.println("wrong format");
}
}
//输出学生成绩
Map<String, List<Matching>> studentToMatching = matchingList.stream().collect(Collectors.groupingBy(matching -> matching.student.student_num));
List<Map.Entry<String, List<Matching>>> entries = new ArrayList<>(studentToMatching.entrySet());
entries.sort((o1, o2) -> o1.getKey().compareTo(o2.getKey()));
for (Map.Entry<String, List<Matching>> entry : entries) {
String studentNum = entry.getKey();
List<Matching> matchings = entry.getValue();
double totalScoreAvg = matchings.stream().mapToDouble(matching -> matching.grade.totalscore).average().orElse(0);
if(totalScoreAvg==-1){
System.out.println(studentNum + " " + matchings.get(0).student.name + " did not take any exams");
}else{
System.out.println(studentNum + " " + matchings.get(0).student.name + " " + (int)totalScoreAvg);
}
}
//输出课程平均成绩
Map<String, List<Matching>> courseToMatching = matchingList.stream()
.filter(matching -> matching.course != null) // 添加非空判断
.collect(Collectors.groupingBy(matching -> matching.course.name));
List<Map.Entry<String, List<Matching>>> entries2 = new ArrayList<>(courseToMatching.entrySet());
entries2.sort((o1, o2) -> {
Collator collator = Collator.getInstance(Locale.CHINA);
return collator.compare(o1.getKey(), o2.getKey());
});
for (Map.Entry<String, List<Matching>> entry : entries2) {
String courseName = entry.getKey();
List<Matching> matchings = entry.getValue();
double regularScoreAvg = matchings.stream().mapToInt(matching -> matching.grade.regularscore).average().orElse(0);
double finalScoreAvg = matchings.stream().mapToInt(matching -> matching.grade.finalscore).average().orElse(0);
double totalScoreAvg = matchings.stream().mapToDouble(matching -> matching.grade.totalscore).average().orElse(0);
if(regularScoreAvg!=0){
System.out.println(courseName + " " + (int)regularScoreAvg + " " + (int)finalScoreAvg + " " + (int)totalScoreAvg);
}else if(totalScoreAvg!=0&®ularScoreAvg==0){
System.out.println(courseName + " " + (int)finalScoreAvg + " " + (int)totalScoreAvg);
}else if(totalScoreAvg==-1){
System.out.println(courseName + " has no grades yet");
}
}
for (String command : commands) {
String[] parts = command.split(" ");
if (parts.length == 3 && courseMap.containsKey(parts[0])) {
if (courseToMatching.get(parts[0]) == null) {
System.out.println(parts[0] + " has no grades yet");
}
}
}
//输出班级平均成绩
Map<String, List<Matching>> classToMatching = matchingList.stream().collect(Collectors.groupingBy(matching -> matching.student.student_num.substring(0, 6)));
List<Map.Entry<String, List<Matching>>> entries1 = new ArrayList<>(classToMatching.entrySet());
entries1.sort((o1, o2) -> {
double avg1 = o1.getValue().stream().mapToDouble(matching -> matching.grade.totalscore).average().orElse(0);
double avg2 = o2.getValue().stream().mapToDouble(matching -> matching.grade.totalscore).average().orElse(0);
return Double.compare(avg2, avg1);
});
for (Map.Entry<String, List<Matching>> entry : entries1) {
String classNum = entry.getKey();
List<Matching> matchings = entry.getValue();
double totalScoreAvg = matchings.stream().mapToDouble(matching -> matching.grade.totalscore).average().orElse(0);
if(totalScoreAvg==-1){
System.out.println(classNum + " has no grades yet");
}else{
System.out.println(classNum + " " + (int)totalScoreAvg);
}
}
}
public static boolean isValid(int score1,int score2, String studentId, String name) {
if (score1 < 0 || score1 > 100) {
return false;
}
if (score2 < 0 || score2 > 100) {
return false;
}
if (studentId.length() != 8 || studentId.length()!=8){
return false;
}
if (name.length() > 10) {
return false;
}
return true;
}
}
7-3 课程成绩统计程序-2
这次题目相比于上次的改动并不算大，多了个 实验课成绩。还是比较好改动的。类的设计相比于上次并于改动。学生类中多了个成绩属性，用来储存学生的平均成绩。这次换了个排序方法。
这是源代码
import java.text.Collator;
import java.util.*;
import java.util.stream.Collectors;
class Student {
String student_num;
String name;
String averageScore;
public Student(String student_num, String name, String averageScore) {
this.name = name;
this.student_num = student_num;
this.averageScore = averageScore;
}
}
class Course{
String name;
String nature;
String assessment;
public Course(String name,String nature,String assessment){
this.name=name;
this.nature=nature;
this.assessment=assessment;
}
}
class Class{
String num;
ArrayList<Student> studentList=new ArrayList<>();
public Class(String num){
this.num=num;
}
public void Addstudent(Student student){
studentList.add(student);
}
}
class Grade{
int regularscore;
int finalscore;
double totalscore;
public Grade(int regularscore,int finalscore,int totalscore){
this.regularscore=regularscore;
this.finalscore=finalscore;
this.totalscore=totalscore;
}
}
class Matching{
Student student;
Course course;
Grade grade;
public Matching(Student student,Course course,Grade grade){
this.student=student;
this.course=course;
this.grade=grade;
}
}
public class 成绩 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
List<String> commands = new ArrayList<>(); // 存储用户输入的所有指令
HashMap<String, Course> courseMap = new HashMap<>();
List<Class> classList = new ArrayList<>();
List<Matching> matchingList = new ArrayList<>();
while (true) {
String line = input.nextLine();
if (line.equals("end")) {
break;
} else {
commands.add(line); // 将输入存储起来
}
}
input.close();
// 遍历存储的所有指令，并执行相应操作
Set<String> validCourseNatures = new HashSet<>(Arrays.asList("必修", "选修","实验"));
Set<String> validAssessments = new HashSet<>(Arrays.asList("考试", "考察","实验"));
Set<String> studentCoursePairs = new HashSet<>();
for (String command : commands) {
String[] parts = command.split(" ");
if (parts.length >= 4) {
String studentCoursePair = parts[0] + " " + parts[2];
if (studentCoursePairs.contains(studentCoursePair)) {
continue;
} else {
studentCoursePairs.add(studentCoursePair);
}
}
if (command.matches("\\D+\\s\\D+\\s\\D+") && validAssessments.contains(parts[2]) && validCourseNatures.contains(parts[1]) && parts[0].length() < 10) {
if (parts[1].equals("必修") && parts[2].equals("考察")||!parts[1].equals("实验") && parts[2].equals("实验")) {
System.out.println(parts[0] + " : course type & access mode mismatch");
continue;
} else {
if (courseMap.get(parts[0]) != null) {
continue;
} else {
Course course = new Course(parts[0], parts[1], parts[2]);
courseMap.put(parts[0], course);
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d+\\s\\d+") && isValid(Integer.parseInt(parts[4]), Integer.parseInt(parts[3]), parts[0], parts[1],5)) {
Student student = new Student(parts[0], parts[1],null);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && (courseMap.get(parts[2]).nature.equals("必修") || courseMap.get(parts[2]).assessment.equals("考试"))) {
Grade grade = new Grade(Integer.parseInt(parts[3]), Integer.parseInt(parts[4]), (int) (Integer.parseInt(parts[3]) * 0.3 + Integer.parseInt(parts[4]) * 0.7));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0,-1 );
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[2] + " does not exist");
} else if(!courseMap.get(parts[2]).nature.equals("必修") || !courseMap.get(parts[2]).assessment.equals("考试")){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d+") && isValid(0, Integer.parseInt(parts[3]), parts[0], parts[1],5)) {
Student student = new Student(parts[0], parts[1],null);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && courseMap.get(parts[2]).nature.equals("选修")) {
Grade grade = new Grade(0, Integer.parseInt(parts[3]), (int) Integer.parseInt(parts[3]));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[2] + " does not exist");
} else if(!courseMap.get(parts[2]).nature.equals("选修")){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
}else if(courseMap.containsKey(parts[2]) && courseMap.get(parts[2]).nature.equals("实验")&&isValid(0,0,parts[0],parts[1],Integer.parseInt(parts[3]))){
Student student = new Student(parts[0], parts[1],null);
int total=0;
boolean flag=true;
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && courseMap.get(parts[2]).nature.equals("实验")&&parts.length==Integer.parseInt(parts[3])+4) {
for(int i=4;i< parts.length;i++){
if(Integer.parseInt(parts[i])<0||Integer.parseInt(parts[i])>100){
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
System.out.println("worng format");
flag=false;continue;
}else {
total+= Integer.parseInt(parts[i]);
}
}
if(flag==false)continue;
Grade grade = new Grade(0, 0, total/Integer.parseInt(parts[3]));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[2] + " does not exist");
} else if(parts.length!=Integer.parseInt(parts[3])+4){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}else if(Integer.parseInt(parts[3])<4||Integer.parseInt(parts[3])>9){
System.out.println("wrong format");
}
}
}else {
System.out.println("wrong format");
}
}
//输出学生所有课程平均分
printStudentAverageGrades(matchingList);
printCourseAndClassAverageGrades(courseMap, matchingList);
}
public static boolean isValid(int score1,int score2, String studentId, String name,int num) {
if (score1 < 0 || score1 > 100) {
return false;
}
if (score2 < 0 || score2 > 100) {
return false;
}
if (studentId.length() != 8 || !studentId.matches("\\d{8}")) {
return false;
}
if (name.length() > 10) {
return false;
}
if(num>9||num<4){
return false;
}
return true;
}
public static void printStudentAverageGrades(List<Matching> matchingList) {
Map<String, List<Matching>> studentMap = new HashMap<>();
for (Matching matching : matchingList) {
String studentId = matching.student.student_num;
if (!studentMap.containsKey(studentId)) {
studentMap.put(studentId, new ArrayList<>());
}
studentMap.get(studentId).add(matching);
}
List<Student> students = new ArrayList<>();
for (String studentId : studentMap.keySet()) {
List<Matching> matchings = studentMap.get(studentId);
double totalScore = 0;
int courseCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
courseCount++;
}
}
double averageScore = courseCount == 0 ? -1 : totalScore / courseCount;
Student student = matchings.get(0).student;
students.add(new Student(student.student_num, student.name, averageScore < 0 ? "did not take any exams" : String.valueOf((int) averageScore)));
}
students.sort(Comparator.comparing(s -> s.student_num));
for (Student student : students) {
System.out.println(student.student_num + " " + student.name + " " + student.averageScore);
}
}
public static void printCourseAndClassAverageGrades(Map<String, Course> courseMap, List<Matching> matchingList) {
Map<String, List<Matching>> courseMatchings = new HashMap<>();
for (Matching matching : matchingList) {
if (matching.course != null) {
Course course = courseMap.get(matching.course.name);
String courseName = matching.course.name;
if (!courseMatchings.containsKey(courseName)) {
courseMatchings.put(courseName, new ArrayList<>());
}
courseMatchings.get(courseName).add(matching);
}
}
List<Course> courses = new ArrayList<>(courseMap.values());
courses.sort(Comparator.comparing(c -> c.name));
for (Course course : courses) {
if (!courseMatchings.containsKey(course.name)) {
System.out.println(course.name + " has no grades yet");
continue;
}
List<Matching> matchings = courseMatchings.get(course.name);
if (course.nature.equals("实验")) {
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(course.name + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
double totalRegularScore = 0;
double totalFinalScore = 0;
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalRegularScore += matching.grade.regularscore;
totalFinalScore += matching.grade.finalscore;
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageRegularScore = studentCount == 0 ? -1 : totalRegularScore / studentCount;
double averageFinalScore = studentCount == 0 ? -1 : totalFinalScore / studentCount;
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
if (averageRegularScore == 0) {
System.out.println(course.name + " " + (averageFinalScore < 0 ? "has no grades yet" : (int) averageFinalScore) + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
System.out.println(course.name + " " + (averageRegularScore < 0 ? "has no grades yet" : (int) averageRegularScore) + " " + (averageFinalScore < 0 ? "has no grades yet" : (int) averageFinalScore) + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
}
Map<String, List<Matching>> classMatchings = new HashMap<>();
for (Matching matching : matchingList) {
String classNum = matching.student.student_num.substring(0, 6);
if (!classMatchings.containsKey(classNum)) {
classMatchings.put(classNum, new ArrayList<>());
}
classMatchings.get(classNum).add(matching);
}
List<String> classNums = new ArrayList<>(classMatchings.keySet());
classNums.sort(Comparator.naturalOrder());
for (String classNum : classNums) {
List<Matching> matchings = classMatchings.get(classNum);
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(classNum + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
}
7-2 课程成绩统计程序-3
这次题目相比于上次修改了实验课的记录方式，还有可以改动考试课的权重。依旧是输入层面的改动。这次在课程类中添加了一个数组，用来储存权重。
以下是源代码
import java.text.Collator;
import java.util.*;
import java.util.stream.Collectors;
class Student {
String student_num;
String name;
String averageScore;
public Student(String student_num, String name, String averageScore) {
this.name = name;
this.student_num = student_num;
this.averageScore = averageScore;
}
}
class Course{
String name;
String nature;
String assessment;
int i=10;
double[] weight=new double[i];
public Course(String name,String nature,String assessment){
this.name=name;
this.nature=nature;
this.assessment=assessment;
}
public void initWeight(int size) {
weight = new double[size];
}
}
class Class{
String num;
ArrayList<Student> studentList=new ArrayList<>();
public Class(String num){
this.num=num;
}
public void Addstudent(Student student){
studentList.add(student);
}
}
class Grade{
int regularscore;
int finalscore;
double totalscore;
public Grade(int regularscore,int finalscore,double totalscore){
this.regularscore=regularscore;
this.finalscore=finalscore;
this.totalscore=totalscore;
}
}
class Matching{
Student student;
Course course;
Grade grade;
public Matching(Student student,Course course,Grade grade){
this.student=student;
this.course=course;
this.grade=grade;
}
}
public class Main {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
List<String> commands = new ArrayList<>(); // 存储用户输入的所有指令
HashMap<String, Course> courseMap = new HashMap<>();
List<Class> classList = new ArrayList<>();
List<Matching> matchingList = new ArrayList<>();
while (true) {
String line = input.nextLine();
if (line.equals("end")) {
break;
} else {
commands.add(line); // 将输入存储起来
}
}
input.close();
// 遍历存储的所有指令，并执行相应操作
Set<String> validCourseNatures = new HashSet<>(Arrays.asList("必修", "选修","实验"));
Set<String> validAssessments = new HashSet<>(Arrays.asList("考试", "考察","实验"));
Set<String> studentCoursePairs = new HashSet<>();
for (String command : commands) {
String[] parts = command.split(" ");
if (parts.length >= 4) {
String studentCoursePair = parts[0] + " " + parts[2];
if (studentCoursePairs.contains(studentCoursePair)) {
continue;
} else {
studentCoursePairs.add(studentCoursePair);
}
}
if (validAssessments.contains(parts[2]) && validCourseNatures.contains(parts[1]) && parts[0].length() < 10) {
if (parts[1].equals("必修") && parts[2].equals("考察")||!parts[1].equals("实验") && parts[2].equals("实验")) {
System.out.println(parts[0] + " : course type & access mode mismatch");
continue;
}
if((parts[2].equals("实验")&&(Integer.parseInt(parts[3])<=3&&Integer.parseInt(parts[3])>=10))){
continue;
}
if(parts[1].equals("必修")||parts[2].equals("考试")){
if(courseMap.get(parts[1])==null){
Course course = new Course(parts[0], parts[1], parts[2]);
course.weight[0]=Double.parseDouble(parts[3]);
course.initWeight(2);course.i=2;
course.weight[1]=Double.parseDouble(parts[3]);
double sum=course.weight[0]+course.weight[1];
if(sum!=1.0){
System.out.println(parts[0] + " weight value error");
continue;
}
courseMap.put(parts[0], course);
}else{
continue;
}
}
else if(parts[2].equals("考察")){
if(courseMap.get(parts[0])==null){
Course course = new Course(parts[0], parts[1], parts[2]);
courseMap.put(parts[0], course);
}else{
continue;
}
}
else if(parts[2].equals("实验")){
if(parts.length!=4+Integer.parseInt(parts[3])){
System.out.println(parts[0] + " : number of scores does not match");
continue;
}else if(courseMap.get(parts[1])==null){
Course course = new Course(parts[0], parts[1], parts[2]);
course.initWeight(Integer.parseInt(parts[3]));double sum=0;
course.i=Integer.parseInt(parts[3]);
for(int j=0;j<Integer.parseInt(parts[3]);j++){
course.weight[j]=Double.parseDouble(parts[4+j]);
sum+=Double.parseDouble(parts[4+j]);
}
if(sum!=1.0){
System.out.println(parts[0] + " : weight value error");
continue;
}
courseMap.put(parts[0], course);
}else{
continue;
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d+\\s\\d") && isValid(Integer.parseInt(parts[4]), Integer.parseInt(parts[3]), parts[0], parts[1],5)) {
Student student = new Student(parts[0], parts[1],null);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && (courseMap.get(parts[2]).nature.equals("必修") || courseMap.get(parts[2]).assessment.equals("考试"))) {
Grade grade = new Grade(Integer.parseInt(parts[3]), Integer.parseInt(parts[4]), (int) ((Integer.parseInt(parts[3]) * courseMap.get(parts[2]).weight[0] + Integer.parseInt(parts[4]) * courseMap.get(parts[2]).weight[0])));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0,-1 );
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[0]+" "+parts[1]+" "+parts[2] + " : does not exist");
} else if(courseMap.get(parts[2]) != null&&!courseMap.get(parts[2]).nature.equals("必修") || !courseMap.get(parts[2]).assessment.equals("考试")){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
} else if (command.matches("\\d+\\s\\D+\\s\\D+\\s\\d") && isValid(0, Integer.parseInt(parts[3]), parts[0], parts[1],5)) {
Student student = new Student(parts[0], parts[1],null);
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && courseMap.get(parts[2]).nature.equals("选修")) {
Grade grade = new Grade(0, Integer.parseInt(parts[3]), (int) Integer.parseInt(parts[3]));
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[0]+" "+parts[1]+" "+parts[2] + " : does not exist");
} else if(!courseMap.get(parts[2]).nature.equals("选修")){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
}else if(courseMap.containsKey(parts[2]) && courseMap.get(parts[2]).nature.equals("实验")&&isValid(0,0,parts[0],parts[1],courseMap.get(parts[2]).i )){
Student student = new Student(parts[0], parts[1],null);
double total=0;
boolean flag=true;
for (Class classlist : classList) {
if (classlist.num.equals(parts[0].substring(0, 6))) {
classlist.Addstudent(student);
}
}
if (courseMap.get(parts[2]) != null && courseMap.get(parts[2]).nature.equals("实验")&&parts.length==3+courseMap.get(parts[2]).i) {
for(int i=3;i< parts.length;i++){
if(Integer.parseInt(parts[i])<0||Integer.parseInt(parts[i])>100){
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
System.out.println("worng format");
flag=false;continue;
}else {
total+= Integer.parseInt(parts[i])*courseMap.get(parts[2]).weight[i-3];
}
}
if(flag==false){
continue;
}
Grade grade = new Grade(0, 0, (int)total);
Matching matching = new Matching(student, courseMap.get(parts[2]), grade);
matchingList.add(matching);
} else {
Grade grade = new Grade(0, 0, -1);
Matching matching = new Matching(student, courseMap.get(parts[0]), grade);
matchingList.add(matching);
if (courseMap.get(parts[2]) == null) {
System.out.println(parts[0]+" "+parts[1]+" "+parts[2] + " : does not exist");
} else if(parts.length!=3+courseMap.get(parts[2]).i){
System.out.println(parts[0] + " " + parts[1] + " " + ": access mode mismatch");
}
}
} else if (courseMap.get(parts[2])==null) {
System.out.println(parts[0]+" "+parts[1]+" "+parts[2] + " : does not exist");
} else {
System.out.println("wrong format");
}
}
//输出学生所有课程平均分
printStudentAverageGrades(matchingList);
printCourseAndClassAverageGrades(courseMap, matchingList);
}
public static boolean isValid(int score1,int score2, String studentId, String name,int num) {
if (score1 < 0 || score1 > 100) {
return false;
}
if (score2 < 0 || score2 > 100) {
return false;
}
if (studentId.length() != 8 || !studentId.matches("\\d{8}")) {
return false;
}
if (name.length() > 10) {
return false;
}
if(num > 9 || num < 4){
return false;
}
return true;
}
public static void printStudentAverageGrades(List<Matching> matchingList) {
Map<String, List<Matching>> studentMap = new HashMap<>();
for (Matching matching : matchingList) {
String studentId = matching.student.student_num;
if (!studentMap.containsKey(studentId)) {
studentMap.put(studentId, new ArrayList<>());
}
studentMap.get(studentId).add(matching);
}
List<Student> students = new ArrayList<>();
for (String studentId : studentMap.keySet()) {
List<Matching> matchings = studentMap.get(studentId);
double totalScore = 0;
int courseCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
courseCount++;
}
}
double averageScore = courseCount == 0 ? -1 : totalScore / courseCount;
Student student = matchings.get(0).student;
students.add(new Student(student.student_num, student.name, averageScore < 0 ? "did not take any exams" : String.valueOf((int) averageScore)));
}
students.sort(Comparator.comparing(e -> e.student_num));
for (Student student : students) {
System.out.println(student.student_num + " " + student.name + " " + student.averageScore);
}
}
public static void printCourseAndClassAverageGrades(Map<String, Course> courseMap, List<Matching> matchingList) {
Map<String, List<Matching>> courseMatchings = new HashMap<>();
for (Matching matching : matchingList) {
if (matching.course != null) {
Course course = courseMap.get(matching.course.name);
String courseName = matching.course.name;
if (!courseMatchings.containsKey(courseName)) {
courseMatchings.put(courseName, new ArrayList<>());
}
courseMatchings.get(courseName).add(matching);
}
}
List<Course> courses = new ArrayList<>(courseMap.values());
courses.sort(Comparator.comparing(e -> e.name));
for (Course course : courses) {
if (!courseMatchings.containsKey(course.name)) {
System.out.println(course.name + " has no grades yet");
continue;
}
List<Matching> matchings = courseMatchings.get(course.name);
if (course.nature.equals("实验")) {
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(course.name + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
double totalRegularScore = 0;
double totalFinalScore = 0;
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalRegularScore += matching.grade.regularscore;
totalFinalScore += matching.grade.finalscore;
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageRegularScore = studentCount == 0 ? -1 : totalRegularScore / studentCount;
double averageFinalScore = studentCount == 0 ? -1 : totalFinalScore / studentCount;
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
if (averageRegularScore == 0) {
System.out.println(course.name + " "+ (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
System.out.println(course.name +" " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
}
Map<String, List<Matching>> classMatchings = new HashMap<>();
for (Matching matching : matchingList) {
String classNum = matching.student.student_num.substring(0, 6);
if (!classMatchings.containsKey(classNum)) {
classMatchings.put(classNum, new ArrayList<>());
}
classMatchings.get(classNum).add(matching);
}
List<String> classNums = new ArrayList<>(classMatchings.keySet());
classNums.sort(Comparator.naturalOrder());
for (String classNum : classNums) {
List<Matching> matchings = classMatchings.get(classNum);
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(classNum + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
}
采坑心得：
这系列题目的难度主要在于给数据进行计算和排序,需要写比较多的代码。还有一些要注意的地方。首先，在修改类结构时，要注意将原来的继承关系改为组合关系。其次，在输入课程信息时，要注意输入的课程性质和考核方式是否匹配。此外，在输入实验课程信息时，要注意输入的分项成绩数量值和分项成绩权重的个数是否匹配。最后，在解析考试课、实验课时，要检查分项成绩权重值的总和是否等于1。
改进建议：
排序时可以使用一些简单的方法去简化排序所要写的代码，如lambda表达式。举个列子
public static void printCourseAndClassAverageGrades(Map<String, Course> courseMap, List<Matching> matchingList) {
Map<String, List<Matching>> courseMatchings = new HashMap<>();
for (Matching matching : matchingList) {
if (matching.course != null) {
Course course = courseMap.get(matching.course.name);
String courseName = matching.course.name;
if (!courseMatchings.containsKey(courseName)) {
courseMatchings.put(courseName, new ArrayList<>());
}
courseMatchings.get(courseName).add(matching);
}
}
List<Course> courses = new ArrayList<>(courseMap.values());
courses.sort(Comparator.comparing(e -> e.name));
for (Course course : courses) {
if (!courseMatchings.containsKey(course.name)) {
System.out.println(course.name + " has no grades yet");
continue;
}
List<Matching> matchings = courseMatchings.get(course.name);
if (course.nature.equals("实验")) {
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(course.name + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
double totalRegularScore = 0;
double totalFinalScore = 0;
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalRegularScore += matching.grade.regularscore;
totalFinalScore += matching.grade.finalscore;
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageRegularScore = studentCount == 0 ? -1 : totalRegularScore / studentCount;
double averageFinalScore = studentCount == 0 ? -1 : totalFinalScore / studentCount;
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
if (averageRegularScore == 0) {
System.out.println(course.name + " "+ (averageScore < 0 ? "has no grades yet" : (int) averageScore));
} else {
System.out.println(course.name +" " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
}
Map<String, List<Matching>> classMatchings = new HashMap<>();
for (Matching matching : matchingList) {
String classNum = matching.student.student_num.substring(0, 6);
if (!classMatchings.containsKey(classNum)) {
classMatchings.put(classNum, new ArrayList<>());
}
classMatchings.get(classNum).add(matching);
}
List<String> classNums = new ArrayList<>(classMatchings.keySet());
classNums.sort(Comparator.naturalOrder());
for (String classNum : classNums) {
List<Matching> matchings = classMatchings.get(classNum);
double totalScore = 0;
int studentCount = 0;
for (Matching matching : matchings) {
if (matching.grade.totalscore >= 0) {
totalScore += matching.grade.totalscore;
studentCount++;
}
}
double averageScore = studentCount == 0 ? -1 : totalScore / studentCount;
System.out.println(classNum + " " + (averageScore < 0 ? "has no grades yet" : (int) averageScore));
}
}
在代码中，课程列表 courses 使用了 Collections.sort() 方法进行排序，传入了一个 lambda 表达式作为比较器，按照课程名称的字典顺序进行排序。班级号列表 classNums 也使用了 Collections.sort() 方法进行排序，传入了 Comparator.naturalOrder() 作为比较器，按照班级号的自然顺序进行排序。
总结：
通过这几次作业，我还是自学到了挺多东西的如lambda表达式，非常实用，许多地方都可以用到。还有Collections类的用法，排序时非常方便。
标签：String,grade,BLOG,parts,student,new,matching From： https://www.cnblogs.com/wsdjb/p/17499401.html