Given an array of integers, find if the array contains any duplicates. bool containsDuplicate(vector& nums) { unordered_set s (nums.begin(), nums.end()); return s.size() != nums.size(); }

"It's harder to read code than to write it." - Joel Spolsky

"Proof by analogy is fraud." - Bjarne Stroustrup

How do you handle data that can't fit/be processed by one machine? Main Partition techniques - Range based [A-C,D-G,...] Efficient range queries. Risk of hot spots -> Split the partition - Hash based. No range queries but distributes load evenly. Check "Consistent hashing"

A project's bus factor is the number of team members who would put the project in jeopardy if run over by a bus (or get sick, vacation, resign, ...) Strive to increase this number. Ex: - Write good doc - Code reviews - Pair programming to spread knowledge of the code base

Fast, Cheap, Reliable You can only pick two

You can use hash tables to avoid creating multiple immutable data structures with the same content.

When all you have is a hammer, everything starts to look like a nail

Difference between x86, i386 and x64: - x86 is a family of instruction set architectures based on Intel 8086 - i386 or x86-32 is the 32-bit architecture of the x86 family - x64 is the 64-bit instruction set of the x86 family. Also called amd64, designed by AMD

The expected constant time property of a hash table assumes that the load factor be kept below a certain bound.

The best architectures, requirements, and designs emerge from self-organizing teams agilemanifesto .org

j++; // increment j Don't be this person

Radix sort is an algorithm that sorts numbers by processing individual digits.

Resume tip for junior devs: Don't put junior on your CV/portfolio. Let them decide where you fit based on your skills.

Check if there's a root-to-leaf path such that the sum of all the along the path equals a given sum. bool f(Node* r, int sum) { if(!r) return false; if(!r->left && !r->right && sum == r->val) return true; return f(r->left, sum - r->val) || f(r->right, sum - r->val); }

Similar GCP/AWS services - Compute Engine ~ Elastic Compute Cloud - Kubernetes Engine ~ Elastic Kubernetes/Container Service - App Engine ~ Elastic Beanstalk - Cloud Functions ~ Lambdas

The execute permission bit for a directory is often called the search bit, because if you want to open a file by name, you need to have execute permission in each directory in the pathname, e.g. /home/username This is different from read permission: list content of a directory

PHP (Personal Homepage) developed by Rasmus Lu Dorf in 1995 It is mostly used in web development. WordPress is written in PHP

Example PHP page

Why backend VS frontend? Think of them as your primary and secondary strenghts Combining of both is the most entrepreneurial - HTML - CSS - JavaScript - Python + Django - MySQL/MongoDB - Some Linux You can launch full websites on your own with a stack similar to this.

Unix pipes cheatsheet a | bPipe: connect output from a to input of b < redirect standard input from file > redirect standard output to file 2> redirect standard error to file >> append standard output to file 2>> append standard error to file