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  • Given a file (which can be considered as a String…

     Akash  updated 11 months, 3 weeks ago 2 Members · 2 Posts
  • Akash 


    Given a file (which can be considered as a String with comma delimiter for the complexity of the question) of usernames and a value k, find top k usernames (with number of logins) who logged into the system the most.

    For example –


    User (String) = user1, user4, user2, user1, user3, user1, user2, user3

    k (int) = 2


    user1 (3)

    user2 (2)

    user3 (2)

    – Both user2 and user3 should be included since both has same number of logins

    Write a java method to find the output with best time and space complexity.

  • Akash 


    package myProject;

    import java.awt.color.CMMException;

    import java.util.ArrayList;

    import java.util.Collections;

    import java.util.Comparator;

    import java.util.HashMap;

    import java.util.List;

    import java.util.Map.Entry;

    public class MaximumNumberOfusersLoggedin {

    public static void main(String[] args) {

    // TODO Auto-generated method stub

    String users = “user1, user4, user2, user1, user3, user1, user2, user3”;

    int k = 3;

    HashMap<String, Integer> hm = new HashMap<>();

    for (String user : users.split(“,”)) {

    String temp = user.trim();

    if (hm.containsKey(temp))

    hm.put(temp, hm.get(temp) + 1);


    hm.put(temp, 1);


    List<Entry<String, Integer>> list=new ArrayList<>(hm.entrySet());

    Collections.sort(list, new Comparator<Entry<String, Integer>>() {


    public int compare(Entry<String, Integer> o1,

    Entry<String, Integer> o2) {

    // TODO Auto-generated method stub

    return o2.getValue()-o1.getValue();



    for(int i=0;i<k;i++)


    Entry<String, Integer> entry=list.get(i);




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0 of 0 posts June 2018
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