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System Design - Matching/Real-time Systems 方法论框架
System Design 匹配/实时系统面试方法论System Design Matching/Real-time Systems Methodology🎯 核心问题：这类题目的特征Core Question: Characteristics of These Problems这是 Uber 面试的核心！ 匹配系统（Matching Systems）和实时系统（Real-time Systems）是 Uber 业务的核心。This is the core of Uber intervie...…
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System Design - Driver Heat Map 方法论框架
System Design 司机热力图面试方法论System Design Driver Heat Map Methodology🎯 核心问题：Driver Heat Map 的挑战Core Question: Challenges of Driver Heat Map这是 Uber 面试的高频题！ Driver Heat Map 需要实时聚合大量地理位置数据，展示司机密度分布。This is a high-frequency Uber interview question! Driver...…
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System Design - Aggregation/Analytics 方法论框架
System Design 聚合/分析系统面试方法论System Design Aggregation/Analytics Methodology🎯 核心问题：这类题目与 Search 的区别Core Question: Difference from Search Problems这不是 Search！ 这是 Aggregation/Analytics 系统设计。This is NOT Search! This is Aggregation/Analytics system design...…
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System Design - YouTube Top K
Design YouTube Top KUnderstanding the ProblemTop-K is a classic system design problem which has a ton (!) of different variants. As such, each interview can be a little unique. In this writeup, we’ll walk through the problem of designing a top-K s...…
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System Design - Robinhood
Common ProblemsDesign RobinhoodUnderstanding the Problem📈 What is Robinhood? Robinhood is a commission-free trading platform for stocks, ETFs, options, and cryptocurrencies. It features real-time market data and basic order management. Robinhood i...…
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System Design - Add click Aggregator
Common ProblemsDesign Ad Click AggregatorUnderstanding the Problem🖱️ What is an Ad Click Aggregator An Ad Click Aggregator is a system that collects and aggregates data on ad clicks. It is used by advertisers to track the performance of their ads ...…
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UB
跳跃游戏Given an array, representing a jump game starting from the first position. You can jump right either 1 step or x steps, where x is a prime number with the last digit as 3. Each position has a value, determine the maximum sum of values on a pat...…
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Matrix area sum using prefix sum
Matrix Prefix Sumint[][] pre;public void build(int[][] grid) { int n = grid.length; int m = grid[0].length; pre = new int[n + 1][m + 1]; for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) { pre[i + 1][j +...…
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Minimum Spanning Tree
Note that MST only exists in undirected graphKruskal algorithm (most common case) O(n + m) + O(mlogm) sort all edges in ascending order by weight, and start considering edges from the smallest weight. If adding the current edge does no...…
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System design - ticket Master
Common ProblemsDesign TicketmasterUnderstanding the Problem🎟️ What is Ticketmaster? Ticketmaster is an online platform that allows users to purchase tickets for concerts, sports events, theater, and other live entertainment.Functional Requirements...…
