代碼

import java.util.*;
class ScoreRecord {private String studentId;private String name;private String subject;private int score;public ScoreRecord(String studentId, String name, String subject, int score) {this.studentId = studentId;this.name = name;this.subject = subject;this.score = score;}public String getStudentId() { return studentId; }public String getName() { return name; }public String getSubject() { return subject; }public int getScore() { return score; }
}public class StudentScoreAnalysis_NoStream {public static void main(String[] args) {String[] scores = {"S1001,張三,數學,95","S1002,李四,數學,76","S1003,王五,數學,59","S1001,張三,英語,88","S1002,李四,英語,90","S1003,王五,英語,66","S1001,張三,物理,91","S1002,李四,物理,54","S1003,王五,物理,73","S1004,趙六,數學,88","S1004,趙六,英語,92","S1004,趙六,物理,85"};// 0. 構造ScoreRecord集合List<ScoreRecord> recordList = new ArrayList<>();for (int i = 0; i < scores.length; i++) {String[] parts = scores[i].split(",");recordList.add(new ScoreRecord(parts[0], parts[1], parts[2], Integer.parseInt(parts[3])));}// 1. 列出所有學生姓名System.out.println("-------------------");Set<String> studentNames = new TreeSet<>();for (ScoreRecord r : recordList) {studentNames.add(r.getName());}System.out.println("列出所有學生姓名 : " + studentNames);// 2. 每個學生總分System.out.println("-------------------");Map<String, Integer> totalScores = new HashMap<>();for (ScoreRecord r : recordList) {if(totalScores.containsKey(r.getName())){int currentScore = totalScores.get(r.getName());currentScore+=r.getScore();totalScores.put(r.getName(),currentScore);}else {totalScores.put(r.getName(),r.getScore());}}System.out.println("每個學生總分");for (Map.Entry<String, Integer> e : totalScores.entrySet()) {System.out.println(e.getKey()+":"+e.getValue());}// 找出總分最高學生System.out.println("-------------------");String topStudent = "";int maxTotal = Integer.MIN_VALUE;for (Map.Entry<String, Integer> e : totalScores.entrySet()) {if (e.getValue() > maxTotal) {maxTotal = e.getValue();topStudent = e.getKey();}}System.out.println("總分最高學生: " + topStudent + " (" + maxTotal + ")");// 6. 每個學生平均分System.out.println("-------------------");Map<String, Integer> sumScores = new HashMap<>();Map<String, Integer> countScores = new HashMap<>();for (ScoreRecord r : recordList) {sumScores.put(r.getName(), sumScores.getOrDefault(r.getName(), 0) + r.getScore());countScores.put(r.getName(), countScores.getOrDefault(r.getName(), 0) + 1);}for (String name : sumScores.keySet()) {double avg = sumScores.get(name) * 1.0 / countScores.get(name);System.out.printf("%s: %.2f%n", name, avg);}// 5. 不及格學生記錄System.out.println("-------------------");System.out.println("不及格記錄:");for (ScoreRecord r : recordList) {if (r.getScore() < 60) {System.out.println(r.getName() + " - " + r.getSubject() + ": " + r.getScore());}}// 3. 每門課程的最高分System.out.println("-------------------");Map<String, ScoreRecord> subjectTop = new HashMap<>();for (ScoreRecord r : recordList) {if (!subjectTop.containsKey(r.getSubject()) ||r.getScore() > subjectTop.get(r.getSubject()).getScore()) {subjectTop.put(r.getSubject(), r);}}System.out.println("每門課程的最高分:");for (String subject : subjectTop.keySet()) {ScoreRecord rec = subjectTop.get(subject);System.out.println(subject + ": " + rec.getName() + " (" + rec.getScore() + ")");}// 7. 每門課程平均分System.out.println("-------------------");System.out.println("每門課程平均分:");Map<String, Integer> subjectSum = new HashMap<>();Map<String, Integer> subjectCount = new HashMap<>();for (ScoreRecord r : recordList) {subjectSum.put(r.getSubject(), subjectSum.getOrDefault(r.getSubject(), 0) + r.getScore());subjectCount.put(r.getSubject(), subjectCount.getOrDefault(r.getSubject(), 0) + 1);}for (String subject : subjectSum.keySet()) {double avg = subjectSum.get(subject) * 1.0 / subjectCount.get(subject);System.out.printf("%s: %.2f%n", subject, avg);}// 8. 平均分最高課程System.out.println("-------------------");String topSubject = "";double highestAvg = Double.MIN_VALUE;for (String subject : subjectSum.keySet()) {double avg = subjectSum.get(subject) * 1.0 / subjectCount.get(subject);if (avg > highestAvg) {highestAvg = avg;topSubject = subject;}}System.out.println("平均分最高課程: " + topSubject);// 10. 成績明細表System.out.println("-------------------");System.out.println("成績明細表:");Map<String, List<ScoreRecord>> byStudent = new LinkedHashMap<>();for (ScoreRecord r : recordList) {if (!byStudent.containsKey(r.getName())) {byStudent.put(r.getName(), new ArrayList<>());}byStudent.get(r.getName()).add(r);}for (String name : byStudent.keySet()) {System.out.print(name + ": ");List<ScoreRecord> list = byStudent.get(name);for (ScoreRecord r : list) {System.out.print(r.getSubject() + "(" + r.getScore() + ") ");}System.out.println();}}
}

輸出

-------------------
列出所有學生姓名 : [張三, 李四, 王五, 趙六]
-------------------
每個學生總分
李四:220
張三:274
王五:198
趙六:265
-------------------
總分最高學生: 張三 (274)
-------------------
李四: 73.33
張三: 91.33
王五: 66.00
趙六: 88.33
-------------------
不及格記錄:
王五 - 數學: 59
李四 - 物理: 54
-------------------
每門課程的最高分:
物理: 張三 (91)
數學: 張三 (95)
英語: 趙六 (92)
-------------------
每門課程平均分:
物理: 75.75
數學: 79.50
英語: 84.00
-------------------
平均分最高課程: 英語
-------------------
成績明細表:
張三: 數學(95) 英語(88) 物理(91) 
李四: 數學(76) 英語(90) 物理(54) 
王五: 數學(59) 英語(66) 物理(73) 
趙六: 數學(88) 英語(92) 物理(85)