Uber's favorite problem

Welcome back!

This week’s problem might get your heart rate up. Here’s what the expect today:

• Climbing Stairs problem

• CI/CD pipelines

Read time: under 4 minutes

CODING CHALLENGE

Climbing Stairs

You are climbing a staircase. It takes n steps to reach the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Example 1:

Input: n = 2
Output: 2
Explanation: There are two ways to climb to the top.
1. 1 step + 1 step
2. 2 steps

Example 2:

Input: n = 3
Output: 3
Explanation: There are three ways to climb to the top.
1. 1 step + 1 step + 1 step
2. 1 step + 2 steps
3. 2 steps + 1 step

Solve the problem here before reading the solution.

SOLUTION

To solve this problem, we can use dynamic programming. We'll build our solution from the bottom up.

For any step n, the number of ways to reach it is the sum of ways to reach (n-1) and (n-2). This is because we can reach step n by either taking one step from (n-1) or (n-2).

Note that the case where we take 2 steps from (n-2) to (n) is also included in this because we will have to take one step from (n-1) in this case.

The time complexity of this solution is O(n), where n is the number of steps.

COMMUNITY

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CI/CD

CI/CD pipelines

After the recent “Blue Screen of Death” outage at Microsoft, CI/CD has become a hot topic again. Let’s try to understand what CI/CD means.

CI/CD is a set of practices that aims to improve the speed and reliability of software releases.

There are two parts in CI/CD:

• Continuous Integration (CI): CI is about merging code changes frequently. Developers push their code to a shared repository multiple times a day. Each integration is verified by automated builds and tests. This helps catch and fix issues early.

• Continuous Delivery (CD): CD takes the code that passed CI and automatically deploys it to a staging environment. It ensures that the code is always in a deployable state. The final step to production can be manual or automated.

Now, let's see what a CI/CD pipeline might look like:

1. Code commit: Developers push code to the repository.

2. Build: The application is compiled.

3. Unit tests: Small parts of the code are tested individually.

4. Integration tests: Different parts of the application are tested together.

5. Deploy to staging: The application is automatically deployed to a test environment.

6. Acceptance tests: The application is tested in an environment similar to production.

7. Manual approval: A team member reviews and approves the changes.

8. Deploy to production: The application is deployed to the live environment.

9. Post-deployment tests: Final checks are done to ensure everything works in production.

10. Monitoring: Appropriate alarms are set to find issues in the production servers.

Steps 1 to 5 are CI and steps 6-10 are CD.

NEWS

This Week in the Tech World

OpenAI Co-founder Raises $1B: Ilya Sutskever's new AI firm, Safe Superintelligence (SSI), secured $1 billion in funding from major investors. The company aims to develop safe superintelligent AI with a singular focus.

Uber Invests in Wayve: Uber takes a stake in self-driving tech startup Wayve, extending the company's $1 billion funding round. The partnership aims to integrate Wayve's AV2.0 technology into consumer vehicles.

Anthropic Launches Claude Enterprise: AI startup Anthropic released Claude Enterprise, a large-scale AI solution for businesses. The product offers enhanced features like larger context windows and activity feeds for users.

Amazon Checkout Glitch: Amazon's checkout function experienced technical issues during its Labor Day sale, preventing customers from completing purchases. The company's cloud division, AWS, reported no problems.

Alibaba Adds WeChat Pay: Alibaba's Taobao and Tmall e-commerce platforms will now accept payments through Tencent's WeChat Pay. This move could increase Alibaba's market share in less developed parts of China.

Bluesky Gains Users After X Ban: Social media platform Bluesky attracted 2 million new users in a week following Brazil's ban on Elon Musk's X platform. Bluesky is now the top free app on Brazil's iOS App Store.

Hotels Adopt Digital Keys: Major hotel chains are replacing plastic room keys with digital options using Apple Wallet and Google Wallet apps. The shift aims to improve security and convenience for guests.

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BONUS

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Until next time, take care! 🚀

Cheers,

Sahil + Sarra