Score Processing (Java)

7-1 Score Processing (Java) 分数 20

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作者 翁恺 单位 浙江大学

Write a program to process students score data.

The input of your program has lines of text, in one of the two formats:

1. Student's name and student id, as <student id>, <name>, and
2. Score for one student of one course, as <student id>, <course name>, <marks>.

Example of the two formats are:

3190101234, Zhang San
3190101111, Linear Algebra, 89.5

Comma is used as the seperator of each field, and will never be in any of the fields. Notice that there are more than one word for name of the person and name of the course. To make your code easier, the score can be treated as double.

The number of the students and the number of the courses are not known at the beginning. The number of lines are not known at the beginning either. The lines of different format appear in no order. One student may not get enrolled in every course.

The last line has only one word: END to indicate the end of the input.

Your program should read every line in and print out a table of summary in .csv format.

The first line of the output is the table head, consists fields like this:

student id, name, <course name 1>, <course name 2>, ..., average

where the course names are all the courses read, in alphabet order. There should be one space after each comma.

Then each line of the output is data for one student, in the ascended order of their student id, with score of each course, like:

3190101234, Zhang San, 85.0, , 89.5, , , 87.3

For the course that hasn't been enrolled, leave a blank before the comma, and should not get included in the average. The average is rounded to one decimal place. There should be one space after each comma.

All the number output, including the averages should be rounded to one decimal place.

Input Format

As described in the text above.

Output Format

As described in the text above.

Sample Input

3180111435, Operating System, 34.5
3180111430, Linear Algebra, 80
3180111435, Jessie Zhao
3180111430, Zhiwen Yang
3180111430, Computer Architecture, 46.5
3180111434, Linear Algebra, 61.5
3180111434, Anna Teng
END

Sample Output

student id, name, Computer Architecture, Linear Algebra, Operating System, average
3180111430, Zhiwen Yang, 46.5, 80.0, , 63.3
3180111434, Anna Teng, , 61.5, , 61.5
3180111435, Jessie Zhao, , , 34.5, 34.5

 代码长度限制 16 KB 时间限制 400 ms 内存限制 64 M

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import java.util.*;

public class Main {
    public static class Student{
        private String id;
        private String name;
        Map<String,Double> course=new HashMap<>();

        public Student(String id){
            this.id=id;
        }
        public double getAvg(){
            double sum=0.0;
            for(String key:course.keySet()){
                sum+=course.get(key);
            }
            return sum/course.size();
        }
    }
    public static void main(String[] args){
        Map<String,Student> map=new HashMap<>();
        HashSet<String> couName=new HashSet<>();
        //读入数据，整理信息
        Scanner sc=new Scanner(System.in);
        while (!sc.hasNext("END")){
            String line=sc.nextLine();
            String[] str=line.split(", ");

            if(!map.containsKey(str[0])){
                Student student=new Student(str[0]);
                if(str.length==2){
                    student.name=str[1];
                }else if(str.length==3){
                    Double score=Double.parseDouble(str[2]);
                    student.course.put(str[1],score);
                    couName.add(str[1]);
                }
                map.put(str[0],student);

            }else {//如果学生编号已存在map中
                Student student=map.get(str[0]);
                if(str.length==2){
                    student.name=str[1];
                }else if(str.length==3){
                    Double score=Double.parseDouble(str[2]);
                    student.course.put(str[1],score);
                    couName.add(str[1]);
                }
            }
        }
        //打印表头信息
        System.out.print("student id, name, ");
        ArrayList<String> nameList=new ArrayList<>(couName);
        Collections.sort(nameList);//按字母顺序排列
        for(String name:nameList){
            System.out.print(name+", ");
        }
        System.out.println("average");

        //打印学生信息
        List<String> list=new ArrayList<>(map.keySet());
        Collections.sort(list);//按编号升序排序
        for(String key:list){
            Student student=map.get(key);
            System.out.print(student.id+", ");
            System.out.print(student.name+", ");
            for(int i=0;i<nameList.size();i++){
                String name=nameList.get(i);
                if(student.course.containsKey(name)){
                    System.out.print(student.course.get(name)+", ");
                }else {
                    System.out.print(", ");
                }
            }
            System.out.printf("%.1f\n",student.getAvg());
        }
    }
}