LeetCode 217: Contains Duplicate — The HashSet Trick Explained (Java) скачать в хорошем качестве

LeetCode 217: Contains Duplicate — The HashSet Trick Explained (Java)

Tonight I’m tackling LeetCode 217: Contains Duplicate—a simple but foundational problem that teaches the power of frequency-based thinking and the HashSet pattern in Java. I walk through the problem step-by-step: • What the input and output actually represent • How to reason about duplicates using a frequency counter mental model • Why a HashSet is the perfect tool here • Visualizing the algorithm using a Figma whiteboard • Building the solution from scratch using a clean for loop + early return • Debugging a small logic mistake and fixing it live • Submitting the final working Java solution on LeetCode If you're following my nightly problem-solving journey, this one is a great warm-up: lightweight, visual, and conceptually important. Problem Statement: Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct. Timestamps: 0:00 - Intro & Problem Analysis 0:45 - Whiteboarding in Figma (Visualizing the Array) 2:15 - Identifying the Frequency Counter Pattern 3:30 - Coding the Solution (Java) 5:00 - Catching & Fixing the Logic Bug 5:35 - Final Submission & Success 🔁 Topic: Arrays, Sets, Frequency Counting 📚 Difficulty: Easy #LeetCode #Java #Programming #CodingInterview #SoftwareEngineering #Algorithms #HashSet #ContainsDuplicate #LeetCode217 #Figma