Meta lays off 4,000

Welcome back!

We are in the middle of Valentine's week. This week's coding challenge is about finding who's alone!

Today we will cover:

• Single Number

• CAP Theorem and Its Implications

Read time: under 4 minutes

CODING CHALLENGE

Single Number

Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.

You must implement a solution with a linear runtime complexity and use only constant extra space.

Example 1:

Input: nums = [2,2,1]
Output: 1

Example 2:

Input: nums = [4,1,2,1,2]

Output: 4

Example 3:

Input: nums = [1]

Output: 1

Solve the problem here before reading the solution.

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SOLUTION

To solve this problem, we can use the XOR operation. When we XOR a number with itself, the result is 0. When we XOR a number with 0, the result is the number itself.

Since every number appears twice except for one number, if we XOR all numbers together, all the pairs will cancel out (become 0), and we'll be left with the single number.

This approach has linear time complexity O(n) and uses constant extra space O(1) .

SYSTEM DESIGN

CAP Theorem and Its Implications

The CAP theorem tells us that when data is distributed across multiple servers, you can only guarantee two out of these three properties: Consistency, Availability, and Partition Tolerance. Let's understand what these properties mean.

Consistency means all users see the same data at the same time, no matter which server they connect to. If you update some data, all subsequent reads will return that updated value.

Availability means the system remains operational and responds to requests even if some servers fail. Every request to a working server should receive a response, whether it succeeds or fails.

Partition Tolerance means the system continues to work even when network issues prevent servers from communicating with each other. This is crucial in distributed systems because network problems are inevitable.

Since network partitions are inevitable, you're forced to choose between consistency and availability.

If you choose Consistency over Availability (CP systems): The system will return an error or timeout if it can't ensure consistent data. Example: Google Cloud Spanner

If you choose Availability over Consistency (AP systems): The system will return the most recent available data, which might be stale. Example: Apache Cassandra

The choice between CP and AP depends on your application's needs:

• Use CP when accurate data is crucial (banking, stock trading)

• Use AP when the system must stay operational even with stale data (social media, content delivery)

Here's a comparison of CP vs AP systems:

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NEWS

This Week in the Tech World

Meta Begins New Layoffs: Meta started cutting 5% of workforce (4,000 jobs), including some high-performing employees. CEO Zuckerberg says cuts will make room to hire "strongest talent" for AI initiatives.

Tesla China Sales Drop: Tesla's January sales in China fell 11.5% year-over-year to 63,238 units, while local rival BYD grew 47%. Tesla continues price cuts and model updates to stay competitive in the key market.

DeepSeek Impact on AI Industry: While DeepSeek rattled Nvidia's stock, smaller AI chip companies see opportunity. The Chinese startup's efficient model is driving demand for inference chips and spurring industry innovation.

Google Ends Diversity Goals: Google scrapped its diversity targets, citing requirements as a federal contractor under Trump's administration. The company joins other tech giants like Meta and Amazon in rolling back DEI initiatives.

Teladoc Acquires Catapult: Teladoc Health is buying Catapult Health for $65 million to expand preventative care offerings. The deal adds at-home wellness exams and virtual nurse practitioner visits to Teladoc's platform.

Google Revises AI Principles: Google removed its pledge not to use AI for weapons and surveillance from its AI principles. The change reflects growing competition with China and push for government contracts.

BONUS

Just for laughs 😏

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Until next time, take care! 🚀

Cheers,

Sahil + Sarra