Como se preparar para entrevistas na Paypal

+5

Design a URL Shortener

Design a URL shortening service similar to TinyURL that allows users to convert long URLs into short, shareable links and manage their shortened URLs.

+2

Tell me about a project of your choice and its challenges

Tell me about a project where you failed

Leetcode 815. Bus Routes

Given repeating bus routes and start/target stops, find the minimum number of bus rides required to go from source to target (or -1 if impossible). This is solved by modeling routes/stops as a graph (e.g., routes as nodes connected when they share stops) and performing BFS to find the shortest transfer path — note constraints: up to 500 routes and 1e5 total stop entries.

Tell about a time when you had to go against the norm and push for a change

Design a price notification system

Design a price notification system that allows users to track Amazon product prices, subscribe to price drop alerts, and view historical pricing data for items in their wishlist.

Design an Online Game Leaderboard

Design a real-time gaming leaderboard system that displays global top rankings, user's current rank with surrounding players, and rankings within their friends list, handling millions of score updates daily.

Design a Basic Auth System

Design a scalable authentication system that can handle user registration, login, session management, and secure access control across multiple services.

Leetcode 2043. Simple Bank System

Design a Bank class that maintains 1-indexed account balances and supports transfer, deposit, and withdraw operations; each operation must validate account indices and (for withdraw/transfer) sufficient funds, returning true and updating balances on success or false otherwise.

Leetcode 135. Candy

Given a line of children with integer ratings, assign each at least one candy so any child with a higher rating than a neighbor gets more candies, and compute the minimum total required; the core challenge is balancing local increases/decreases across the array (typically handled by scanning increasing/decreasing runs or a two-pass greedy) in linear time.

Leetcode 462. Minimum Moves to Equal Array Elements II

Given an integer array, find the minimum number of ±1 moves needed to make all elements equal — equivalently, choose a target value that minimizes the sum of absolute deviations. This is an L1-minimization problem whose optimal target is any median, so the answer is the sum of |nums[i] − median|.

Review Virtual Credit Card Payment System

Review code that processes payment methods based on business rules, identifying logical issues and implementing new requirements. Analyze program output for given inputs and ensure the system handles various payment scenarios correctly.

Design a Banking System

Design a banking system that allows users to create accounts, manage funds (deposits, withdrawals, transfers), check account balances, and perform core banking operations securely.

Leetcode 2933. High-Access Employees

Given timestamped accesses per employee, find all employees who made three or more accesses within any one-hour period (accesses exactly 60 minutes apart do not count). The core challenge is grouping times by employee and detecting any triple inside a 60-minute window—usually solved by sorting each person's times and using a sliding-window/two-pointer check.