Question

Game CSV Sum with Map

Chuchu and Xyz are playing a game. But this time they've invited their friends!

They've written down their scores in a String like this:

Xyz, 10

Chuchu,5

Sheldon,6

Xyz, 20

Lulu,8

Xyz, 4

The winner of the game is the player with the most total points. For the game above, the winner is Xyz, since she scored 34 points to Chuchu's 5, Sheldon's 6, and Lulu's 8. Note that zero is a valid number of points to have scored and should not be treated separately.

Write a function called winner that determines the winner of the game. It accepts a single String argument containing CSV records as shown above and should return a String containing the winner. If any two players earn the same score you should return "Tie".

A few notes. First, you'll want to use both split and trim, two of our familiar functions for working with String data. Second, while each line will contain a record, there may be extra whitespace surrounding each record. (The data was entered by happy animals.) Third, recall that you can use Integer.parseInt to convert a String to an int. Fourth, if the String passed is null or contains no lines, you should return null.

Finally, unlike the previous version of this problem Chuchu and Xyz are not the only players! They have many friends, some with strange names. So the participants will be different from game to game.

This is a great problem to solve using a map. Here's a solution approach:

1. Parse the CSV and combine all the scores into a map, totaling the score for each player as you go
2. Loop over the map to compute the maximum

You may need to examine the map documentation. But as a helpful note, the keySet Map function will return all of the keys in the map, which you can iterate over:

for (String player : map.keySet()) {

// Etc

}

Answer 1

The solution to this in java is as follows:-

Code-

import java.io.*;
import java.util.*;
import java.nio.file.Files;
import java.nio.file.Paths;

public class Game{
   public static String winner(String records){
       //Checking is records are null
       if(records.isNull())
           return "";
       String []recordList=records.split("\n"); //Creating a list of records
       //For storing the records as a map
       Map<String, Integer> map = new HashMap<String, Integer>();
       //Iterate over the record list and put them in a map
       for(String record:recordList){
           String[] data=record.split(",");
           String name=data[0].trim();
           int points=Integer.parseInt(data[1].trim());
           if (map.containsKey(name))
            {
                map.put(name, map.get(name) + points);
            }
            else
            {
                map.put(name, points);
            }
       }
       //Find the winner based on points
       String winner="";
       int maxpoints=-1;
       //Find the maximum points of a player in the map
       for (Map.Entry<String, Integer> entry : map.entrySet())
        {
           if(entry.getValue()>maxpoints){
               maxpoints=entry.getValue();
               winner=entry.getKey();  
           }
        }
        //Find the number of winners with maximum score
        int countOfWinners=0;
        for (Map.Entry<String, Integer> entry : map.entrySet())
        {
           if(entry.getValue()==maxpoints){
               countOfWinners++;  
           }
        }
        if(countOfWinners==1) //If there is one winner
           return winner;
       else                  //If there are multiple winners
           return "Tie";
   }
   public static void main(String argc[]) throws IOException{
       //Reading contents of the csv file
       String content = new String(Files.readAllBytes(Paths.get("list.csv")));
       System.out.println("Winner of the game: "+winner(content));
   }
}

Code Screenshots-

Outputs-

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