Design questions

 1. Design a Rate Limiter Every company covered this.

Know: Sliding window algorithms, Redis, race condition handling, token bucket vs. leaky bucket models.

2. Design a Chat Application A WhatsApp-style typing indicator alone can drive a 45-minute discussion.

Know: WebSockets, Redis Pub/Sub, message queues, offline message delivery.

3. Design a URL Shortener Appears straightforward. Becomes complex quickly.

Know: Base62 encoding, collision resolution, analytics tracking, Redis-based caching.

4. Design a Notification System

Know: Push vs. pull architecture, Kafka for asynchronous delivery, retry mechanisms, user preference management.

5. Design a Payment System JPMorgan asked this. So did multiple others.

Know: Idempotency keys, Saga pattern, ACID transactions vs. eventual consistency.

6. Design an API Rate Limiter Different from #1. This focuses on distributed system design.

Know: Token bucket algorithms, Redis INCR, Lua scripting, multi-node coordination.

7. Design a Video Streaming Platform

Know: CDN architecture, chunked uploads, adaptive bitrate streaming, large-scale storage systems.

8. Design a Ride-Hailing Application

Know: Real-time location tracking, matching algorithms, surge pricing strategies, live event processing.

9. Design an E-commerce Checkout System

Know: Inventory reservation, flash-sale scalability, payment retry workflows, order state management.

10. Design a Search Autocomplete System

Know: Trie data structures, frequency-based ranking, result caching, sub-100ms latency optimization.

to study

 https://www.reddit.com/r/leetcode/comments/1ota2ac/uber_low_level_design_interview_questions/


https://mockgym.com/roadmaps

https://takeuforward.org/dsa/strivers-sde-sheet-top-coding-interview-problems

To check later palindrom what mistake i did. Earn Inte

 /*

A palindrome is a word that is the same when read left-to-right and right-to-left.  For example, “racecar” is a palindrome.

Given a string, find all of the substrings that are also palindromes.

Example input:

  "racecar"

Example output:

   [“racecar”, “aceca”, “cec”, “r”, “a”, “c”, “e”, “c”, “a”, “r”]

*/

import java.io.*;

import java.util.*;

class Solution {

  public static void main(String[] args) {

    String str = "racecar";

    ArrayList<String> resultSet = new ArrayList<String>();

   /*  

   for(int i = 0; i< str.length(); i++)

    {

       for(int j = i; j< str.length(); j++)

       {

          String subStr =str.substring(i, j+1);

          if(isPalindrome(subStr))

          {

              resultSet.add(subStr);

              System.out.println(subStr);

          }

       }

    }

    */

   int left = 0;

   int right = str.length();

   for(int i = 0; i< str.length(); i++)

   {

          int oddString = isPalindrome(str ,i,i);

          int evenString = isPalindrome(str ,i,i+1);

         

    }

   

   

  }

public static int isPalindrome(String str, int left, int right)

    {

        while(left>=0 && right < str.length() && str.charAt(left) == str.charAt(right))

        {

           

              left--;

              right ++;

               System.out.println(str.substring(left+1, right));

         

        }

       // System.out.println(str.substring(left+1, right));

        return right-left-1;

       

    }

    public static Boolean isPalindrome(String str)

    {

        int left = 0;

        int right = str.length() -1;

        for(int i = left; i< right; i++, right--)

        {

          if(str.charAt(i) != str.charAt(right))

          {

            return false;

          }

         

        }

        return true;

    }

   

}

Coding Leetcode probelm solving skills

 https://asyncthinking.com/p/beating-leetcode-systematic-framework

Company wise interview questions

 https://leettracker-ff.web.app/questions

https://github.com/snehasishroy/leetcode-companywise-interview-questions

g-o-ogle

 // IP --> 10.10.20.1 --> Belong to a Subnet 10.10.0.0/16 16 = 255.255.0.0

// Dest --> Belongs to 10.10.0.0/16 -- //----

// Dest --> Belongs to 10.10.10.0/24 -- G2

// Implement an IP Route Lookup table for IPv4 addresses

// IP address is an 32 bit Integer or 4 Octets

// IP Addr & Subnet Mask =. Network Address

// IP = 10.10.20.1 --> AAA.BBB.CCC.DDD

//                     [A-Z].[A-Z]

//                     [[0-0][0-9[0-9]].[[0-0][0-9[0-9]].[[0-0][0-9[0-9]].[[0-0][0-9[0-9] 

multibit trie

C# javascript interview questions - CC FG

1.  server based connection - what is the page that goes with every request that knows this is the user

2. HTML difference between div and span

3. DOM - what is the tree like and what are its node?

4. .NET feature C# latest

5. 2 reference type - class array

6. var obj

7. Delete truncate

8. clustered non clustered

9. inner join outer join

10. datatypes in javascript

11. Ienumerable List

12. factory pattern

13. DI 

14. Difference between var let