Ice Cream Parlor

IceCreamParlor.java

package com.company;

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;

import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'icecreamParlor' function below.
     *
     * The function is expected to return an INTEGER_ARRAY.
     * The function accepts following parameters:
     *  1. INTEGER m
     *  2. INTEGER_ARRAY arr
     */

    public static List<Integer> icecreamParlor(int m, List<Integer> arr) {


        List<Integer> ans = new ArrayList<>();
        HashMap<Integer,Integer> hmap = new HashMap<>();

        for(int i=0; i<arr.size(); i++){
            if(hmap.containsKey(arr.get(i))){  //Contains key, return answer
                ans.add( hmap.get(arr.get(i)) );
                ans.add( i+1 );
                break;
            }
            hmap.put(m-arr.get(i), i+1 );   //doesnt contain the key, add it
        }

        return ans;
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = null;
        try {
            File f = new File("s.txt");
            if (!f.exists()) {
                System.out.println(f.createNewFile());

            }
            bufferedWriter = new BufferedWriter(new FileWriter(f.getName()));
        } catch (IOException e) {
            e.printStackTrace();
        }

        int t = Integer.parseInt(bufferedReader.readLine().trim());

        BufferedWriter finalBufferedWriter = bufferedWriter;
        IntStream.range(0, t).forEach(tItr -> {
            try {
                int m = Integer.parseInt(bufferedReader.readLine().trim());

                int n = Integer.parseInt(bufferedReader.readLine().trim());

                List<Integer> arr = Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
                        .map(Integer::parseInt)
                        .collect(toList());

                List<Integer> result = Result.icecreamParlor(m, arr);

                finalBufferedWriter.write(
                        result.stream()
                                .map(Object::toString)
                                .collect(joining(" "))
                                + "\n"
                );
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        });

        bufferedReader.close();
        bufferedWriter.close();
    }
}