Background:
~3 years in a FAANG company
Recruiter reached out via LinkedIn
Tier-3 college graduate

Screening round Question
Matching APKs to Devices in Google Play

Round 1:
A DDA is given where each row has 3 elements [c1, c2, cost] which indicates the cost to travel from c1 to c2. Calculate the minimum cost to travel from source city to destination city.
Solution: Dijkstra algo with few modifications
Follow-up: Calculate the minimum cost if we need to pass another city (say c3) while travelling from c1 to c2.
Solution: Calculate the minimum cost to travel from c1 to c3 and then from c3 to c2.
There was more discussion around basics of Dijkstra Algo and Queues in Java.

Round 2:
Very similar to Detonate the maximum bombs
Follow up on creating a generic function if the criteria of connecting nodes is different.

Round 3:
A consultant needs to make profit by travelling in 2 cities. At any point he can choose to stay at city A, stay at city B or travel from one city to another. Input contains 2 arrays which shows the profit he can earn while staying in the city for a particular day. The profit is zero if he chooses to travel.
E.g.: cityA = [23,4,5,10] , cityB = [21,1,10,100]
Max profit = 133, Path = “ATBB”
Calculate the max profit and print the path for it.
Solution: Recursive solution to try all possibilities to figure out max value. Apply dynamic programming to optimise space and time complexity.

Round 4:
Length of longest increasing sequence in a grid
Solution: Apply DFS to explore all the neighbours and Dynamic programming to memoize the answers for already visited nodes.

Googlyness
This is a behavioural round with simple situation based questions based on your past experiences. Being respectful and pleasant is important here. Preparation for this round can be done by reflecting on your past experiences and your goals.
Example questions: Your biggest achievement in your current role, any major changes that you brought in a project, conflicts with manager and colleagues.

Verdict
Got offer for L4 based on my experience and feedbacks from interviews

I have appeared for Google’s interviews for multiple times in the past and have had some learnings with each of my attempt.

• Take your time to prepare. Do not rush into giving an interview just because a recruiter approached you. Companies always have openings and an extra month of preparation can change your end result.
• Know all your basics and invest time in building your intuition instead of getting yourself stuck on complicated problems. Complicated problems are generally not asked but if you are confident about practice you can solve any problem. Also, interviewers can always grill you on basics. For example, if you are using an internal library for min heap make sure you know its internal implementation along with the time complexities.
• Plan your own journey. There is no magic number for numbers of questions to be solved or time taken for preparation. Someone might do it in 2 months with 300 questions and someone else can do it in 6 months with 800 questions. You are the best judge of your own potentail and mistakes.
• Communication is very important so that the interviewer can understand your thought process. Remember these interviews aren’t about quickly reaching the solution and coding it up. The interviewer is evaluating your entire thought process to reach the solution and they’ll be able to do it only when you communicate. At the same time, be a very active listener and try to pick and build on every clue that the interviewer might provide. Make sure to do some mock interviews with some of your friends to perfect this.
• Practice on simple text editors and IDEs with autocomplete disabled. Make sure to write neat and readable code. Create functions for repeated blocks of code. Practice on multiple editors to make sure you are comfortable to code in any unknown editor.
• Be respectful all through the process. The process tends to go for months and at times may take very unexpected turns. It is easy to get frustrated. Having patience and communicating professionally is very important too. At the same time, the recruiter is the source of all the information about the process so keep the communication channel open with the recruiter. They are generally very nice and give all the information that they are allowed to.

The resources that I followed are listed below:
Striver's A2Z DSA Course
Striver's SDE Sheet
Googlyness by Jeff H. Sipe
I prefer to stick to a limited number of resources to avoid repetition and confusion.

I hope the post helps you in your next interview.
Good Luck! :)