java中HashMap中一个键的多个值

Question

Problem

I am struggling to solve a problem where user inputs student name with marks ie [(John,50),(Allex,70),(Tim,80),(Allex,90)].

Now I want average of marks of each student ie [(John,50),(Allex,80),(Tim,80)].

As I was planning to use HashMap in this case but I realized that a single key cannot have multiple values so how can I approach the question using map or another data structure.

Answer 1

Single Key cannot have multiple values but single key can have a single object capable of holding multiple value! Use

HashMap<String, List<Integer>> 

Or you can also use

HashMap<String,List<subject>>

where subject class can have subject name,subject id,etc...