@rkenmi - Search Results

DataFrames (a software engineer's perspective)

What is a DataFrame? A DataFrame is a special data structure used primarily by data scientists and machine learning algorithms. It contains row and column data in tabular fashion by storing metadata about each column and row.

May 2, 2022

Bloom Filter

A set data structure uses a hashing function to store values and to verify if a value exists. Bloom filters are similar in that it uses multiple hashing functions to store values and to verify if a value exists.

October 14, 2019

NumPy vs. Pandas, and other flavors (Dask, Modin, Ray)

... is a Python library for numerical computing that offers multi-dimensional arrays and indices as data structures and additional high-level math utilities. ndarray The unique offering of NumPy is the ndarray data structure, which stands for n-dimensional array.

May 26, 2022

Algorithm Handbook

... to the algorithm handbook wiki! In this wiki you will find a mini-cheat sheet overview of data structures, and examples of their usages in modern languages. Algorithm problems can be found here.

June 18, 2017

B-Trees vs. LSM Trees

... represented as B-Trees or LSM Trees (Log structured merge trees). B-trees are "tried and true" data structures that are popular in database usage, most notably SQL databases. With a B-Tree indexing structure, data is written onto the disk in fixed size page segments.

March 14, 2018

Java Essentials

... (arguably) is because Box Types allow primitive data type values to be stored into useful Java data structures, such as HashMap or ArrayList. Primitive data types do not have enough memory to have their own non-static methods.

March 29, 2019

Build a Trie in Python

... code is viable for a simple implementation and it is easier to write, since tries are recursive data structures in nature. Iterative code however, is faster in the long-run albeit it being trickier to write.

February 3, 2019

4 Line Depth-first Search

Context Depth-first search (DFS) is a common searching algorithm for graphs, alongside Breadth-first search (BFS). DFS is useful for finding ways to solve mazes. It is also a vital ingredient for topological sorting.

May 7, 2017

Google Protocol Buffers

... developer perspective): Create your protobuf definition files (.proto) Define your messages (data structures) and services. Compile the .proto files with protobuf, generating .

June 3, 2018

Design Concepts

In this article, I want to go over some fundamental design concepts that are useful for coming up with system design. Requirements Functional Requirements Describes specific behaviors i.e. If a URL is generated, it is composed of a Base64 encoded alias Non-functional Requirements Describes architectural requirements i.

November 20, 2019

Data stores in Software Architectures

... queries, i.e. geohash, quadtrees. Since quadtrees are a general purpose, in-memory 4-child tree data structures, there is no specific data store that supports using quadtrees for geospatial queries.

July 19, 2021

Comparison Charts of File Storage Formats

Big Data Encodings These encodings are often used with HDFS or some other distributed file system. Since the data can be as large as terabytes or petabytes, it is crucial to encode files in a space optimal way and also allow themselves to be read or written in an optimal way.

January 24, 2022

Scanning for memory addresses with Cheat Engine and ZSNES

... great way to really dive deep into computer science fundamentals (bits, bytes, hexadecimals...), data structures, pointers, the internal workings of memory, and a little bit of assembly language if you want to create new injectable scripts for these games.

July 4, 2017

Iterative In-Order Traversal

Problem Return the values of a binary tree using in-order traversal, iteratively. Input node: Has 3 properties .val: Integer value of the node .left: A pointer to another node object, or None if null .

December 31, 2018

Tenets of Leetcode

... but in a real whiteboard interview it can be time consuming You can type/draw diagrams or data structures if it helps tl;dr: It leads to cleaner code later. You can proof-check with the interviewer if your logic seems off or correct before you even write the real code.

January 27, 2021

Merge k sorted linked lists

Problem Merge \(k\) sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Example: Input: [ 1->4->5, 1->3->4, 2->6 ] Output: 1->1->2->3->4->4->5->6 Input lists - an array of linked list pointers # Definition for singly-linked list.

February 9, 2019

Unique Permutations

... caveat with Python here: Lists cannot be hashed. Lists cannot be hashed because they are mutable data structures. We also don't want to add a set into a set either, since we don't want to store hash tables into hash tables 😦.

February 18, 2019

RDBMS Indexing

Introduction As illustrated in this article, indexing is one of the easiest and most effective tweaks you can add to your SQL database. However, indexing might seem like magic, and you might also not be too sure which field to index in the first place.

January 24, 2021

Python Essentials

Scopes Python has closures, similar to Javascript, since functions are first class objects. But unlike Javascript, there are some subtle gotchas in regards to working with function scopes. nonlocal vs.

April 3, 2019

Javascript Essentials

Hoisting Hoisting is JavaScript's default behavior of moving declarations to the top. Given the following Javascript code, what is the expected output, and why? fcn2(); fcn1(); function fcn2(){ alert("hi"); } var fcn1 = function(){ alert("hey") } The expected output is a pop up alert that says "hi", followed by an error that fcn1 isn't defined.

November 12, 2017

Misconceptions of Software Engineer interviews at FAANG

... you apply for. Focusing on computer science fundamentals and having a good understanding of basic data structures and techniques are far more important than anything else. Studying is not helping Often times, studying by your lonesome and going through a live interview are two different things, completely.

August 15, 2020

CNN - Convolutional Neural Networks

Intuition Compared to RNN, CNN tackles a different kind of issue. When working with images or data that has spatial structure, it turns out that the conventional way of converting the input data to a 1D array (a flattened version) produces some lackluster results.

November 23, 2020

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