Tips for solving leetcode codings interview problems

If input array is sorted then
- Binary search
- Two pointers

If asked for all permutations/subsets then
- Backtracking

If given a tree then
- DFS
- BFS

If given a graph then
- DFS
- BFS

If given a linked list then
- Two pointers

If recursion is banned then
- Stack

If must solve in-place then
- Swap corresponding values
- Store one or more different values in the same pointer

If asked for maximum/minimum subarray/subset/options then
- Dynamic programming

If asked for top/least K items then
- Heap

If asked for common strings then
- Map
- Trie

Else
- Map/Set for O(1) time & O(n) space
- Sort input for O(nlogn) time and O(1) space

Tips for Google Interview Preparation
Now that we know all about the hiring process of Google, here are a few tips which you can use to crack Google’s interview and get a job.

Understand the work culture at Google well - It is always good to understand how the company works and what are the things that are expected out of an employee at Google. This shows that you are really interested in working at Google and leaves a good impression on the interviewer as well.
Be Thorough with Data Structures and Algorithms - At Google, there is always an appreciation for good problem solvers. If you want to have a good impression on the interviewers, the best way is to prove that you have worked a lot on developing your logic structures and solving algorithmic problems. A good understanding of Data Structures and Algorithms and having one or two good projects always earn you brownie points with Amazon.
Use the STAR method to format your Response - STAR is an acronym for Situation, Task, Action, and Result. The STAR method is a structured way to respond to behavioral based interview questions. To answer a provided question using the STAR method, you start by describing the situation that was at hand, the Task which needed to be done, the action taken by you as a response to the Task, and finally the Result of the experience. It is important to think about all the details and recall everyone and everything that was involved in the situation. Let the interviewer know how much of an impact that experience had on your life and in the lives of all others who were involved. It is always a good practice to be prepared with a real-life story that you can describe using the STAR method.
Know and Describe your Strengths - Many people who interview at various companies, stay shy during the interviews and feel uncomfortable when they are asked to describe their strengths. Remember that if you do not show how good you are at the skills you know, no one will ever be able to know about the same and this might just cost you a lot. So it is okay to think about yourself and highlight your strengths properly and honestly as and when required.
Discuss with your interviewer and keep the conversation going - Remember that an interview is not a written exam and therefore even if you come up with the best of solutions for the given problems, it is not worth anything until and unless the interviewer understands what you are trying to say. Therefore, it is important to make the interviewer that he or she is also a part of the interview. Also, asking questions might always prove to be helpful during the interview.

General tips

Always validate input first. Check for inputs that are invalid, empty, negative, or different. Never assume you are given the valid parameters. Alternatively, clarify with the interviewer whether you can assume valid input (usually yes), which can save you time from writing code that does input validation.

Are there any time and space complexities requirements or constraints?

Check for off-by-one errors.

In languages where there are no automatic type coercion, check that concatenation of values are of the same type: int,str, and list.

After you finish your code, use a few example inputs to test your solution.

Is the algorithm supposed to run multiple times, perhaps on a web server? If yes, the input can likely be pre-processed to improve the efficiency in each API call.

Use a mix of functional and imperative programming paradigms:

🔹 Write pure functions as often as possible.
🔹 Use pure functions because they are easier to reason with and can help reduce bugs in your implementation.
🔹 Avoid mutating the parameters passed into your function, especially if they are passed by reference, unless you are sure of what you are doing.
🔹 Achieve a balance between accuracy and efficiency. Use the right amount of functional and imperative code where appropriate. Functional programming is usually expensive in terms of space complexity because of non-mutation and the repeated allocation of new objects. On the other hand, imperative code is faster because you operate on existing objects.
🔹 Avoid relying on mutating global variables. Global variables introduce state.
🔹 Make sure that you do not accidentally mutate global variables, especially if you have to rely on them.

What is the use of Destructor in Java?

What is a Destructor?
A destructor is a special method that gets called automatically as soon as the life-cycle of an object is finished. A destructor is called to de-allocate and free memory. The following tasks get executed when a destructor is called.

- Releasing the release locks
- Closing all the database connections or files
- Releasing all the network resources
- Other Housekeeping tasks
- Recovering the heap space allocated during the lifetime of an object

Destructors in Java also known as finalizers are non-deterministic. The allocation and release of memory are implicitly handled by the garbage collector in Java.

Finalizers in Java have to be implicitly invoked since their invocation is not guaranteed, unlike C# finalizers which get invoked during the .NET run-time.

Let’s take a look at key properties of a destructor:

- Overloading or inheritance is not allowed
- No specification of access modifiers or parameters
- Automatic invocation and no explicit call from the user
- Used in classes but not in structures
- The order of the class varies from the most derived class to the least derived class
- Also called when the object instance is no longer eligible for access
- Used for releasing un-managed resources instead of managed resources held by the object

Garbage Collector
A garbage collector is a program that runs on the Java virtual machine to recover the memory by deleting the objects which are no longer in use or have finished their life-cycle. An object is said to be eligible for garbage collection if and only if the object is unreachable.

Human-Computer Interaction in Game Development with Python
Joseph Thachil George, 2022

Important Sorting Algorithms-

Bubble Sort: Bubble Sort is the most basic sorting algorithm, and it works by repeatedly swapping adjacent elements if they are out of order.

Merge Sort: Merge sort is a sorting technique that uses the divide and conquer strategy.

Quicksort: Quicksort is a popular sorting algorithm that performs n log n comparisons on average when sorting an array of n elements. It is a more efficient and faster sorting algorithm.

Heap Sort: Heap sort works by visualizing the array elements as a special type of complete binary tree known as a heap.

Important Searching Algorithms-

Binary Search: Binary search employs the divide and conquer strategy, in which a sorted list is divided into two halves and the item is compared to the list’s middle element. If a match is found, the middle element’s location is returned.

Breadth-First Search(BFS): Breadth-first search is a graph traversal algorithm that begins at the root node and explores all neighboring nodes.

Depth-First Search(DFS): The depth-first search (DFS) algorithm begins with the first node of the graph and proceeds to go deeper and deeper until we find the goal node or node with no children.

Dynamic Programming (DP) is an algorithmic technique for solving an optimization problem by breaking it down into simpler sub-problems and taking advantage of the fact that the optimal solution to the overall problem is dependent on the optimal solution to its sub-problems.