Day 8 of #BuildUntilHired 🚀 Today I learned the Java Collection Framework: ✅ Queue Interface ArrayDeque LinkedList PriorityQueue ✅ Set Interface HashSet LinkedHashSet TreeSet ✅ Map Interface HashMap and basics of Map collections Also started learning SQL Basics and

#day33 today understand about hashmap, hashset , treemap, linkedlistmap,set , in deep how internally treeset work in Self balancing tree i.e. red black tree Thank you Rohit & Aditya Bhaiya🙏🏻 @CoderArmy @adityatandon02 @rohit_negi9 @java

ABC462 3完 A: Goだと微妙にめんどくさい B: やればいいけど出力が微妙にめんどくさい C: XY両方小さいものがあるか、とりあえずXの小さいほうからTreeSetにYを記録しながら見ていった D: いもす法と尺取り法でやってみたが通らない

Day 7 #SDESheetChallenge ✅ Two Sum – HashMap for complement lookup | O(N) ✅ 4 Sum – Sorting Two Pointers | O(N³) ✅ Longest Consecutive Sequence – Using TreeSet | O(N log N) Solved: 3/3 ✅ @striver_79 @takeUforward_

Day 17 — Today → Collection Framework practice ArrayList vs TreeSet Serialization concepts More hands-on Java problems Day 18 tomorrow. #LearnInPublic #Java #BackendDevelopment #BuildInPublic

Java Sorting │ ├── Comparable │ ├─ داخل الكلاس نفسه │ └─ ترتيب افتراضي (Natural Order) │ ├── Comparator │ ├─ خارجي (Flexible) │ ├─ ترتيب مخصص حسب الحاجة │ └─ يستخدم بكثرة في DSA │ ├── Collections.sort() │ ├─ ترتيب Lists │ ├─ يدعم Comparator │ └─ شائع في المسائل │ ├── Arrays.sort() │ ├─ ترتيب Arrays │ ├─ يدعم Objects Comparator │ └─ سريع وعملي │ ├── Sorting Order │ ├─ Ascending (تصاعدي) │ └─ Descending (تنازلي → reversed) │ ├── PriorityQueue │ ├─ Default: Min Heap │ ├─ يتحول إلى Max Heap بـ Comparator │ └─ مهم في مسائل Top K │ ├── TreeSet / TreeMap │ ├─ ترتيب تلقائي للعناصر │ ├─ يعتمد على Comparator │ └─ مفيد للـ ordered data │ ├── Custom Object Sorting │ ├─ ترتيب حسب أي field │ ├─ name / age / salary │ └─ أساسي في interviews │ └── Use Cases ├─ DSA problems ├─ Greedy algorithms ├─ Scheduling └─ Interview questions

Day 16 — Today → Serialization Collection Framework ArrayList TreeSet ArrayList taught flexibility. TreeSet taught ordering & uniqueness. Collections showed how much Java simplifies development. Day 17 tomorrow. #LearnInPublic #Java #CollectionFramework #BuildInPublic

#Day30 Today I gained a deep understanding of the Iterator and Iterable interfaces, including how they work internally with collections such as ArrayList, TreeSet, HashSet, and HashMap. Thank you Rohit and Aditya bhaiya 🙏🏻 @CoderArmy @adityatandon02 @rohit_negi9 @Java @Oracle

Day 104 : Remove Invalid Parentheses Approach : precompute exact ( and ) to remove via one pass, then DFS keep-or-drop each char while enforcing the close≤open invariant, collecting valid leaves in a TreeSet for dedup lex sort. @geeksforgeeks #gfg

Binary search Dfs Bfs Treemap/treeset questions These are real brain stimulators

𝗝𝗮𝘃𝗮 𝗥𝗼𝗮𝗱𝗺𝗮𝗽 𝟮𝟬𝟮𝟲 𝗝𝗮𝘃𝗮 𝗙𝘂𝗻𝗱𝗮𝗺𝗲𝗻𝘁𝗮𝗹𝘀 Start with the core building blocks of Java programming. 🔹 Syntax & structure 🔹 Variables, data types, operators 🔹 Control flow (if/else, loops, switch) 🔹 Functions / methods 🔹 Arrays & strings 𝗢𝗯𝗷𝗲𝗰𝘁-𝗢𝗿𝗶𝗲𝗻𝘁𝗲𝗱 𝗣𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 (𝗢𝗢𝗣) Java is built on OOP — master it deeply. 🔹 Classes & objects 🔹 Encapsulation, inheritance, polymorphism, abstraction 🔹 Interfaces & abstract classes 🔹 Constructors & method overloading 🔹 Access modifiers 𝗝𝗮𝘃𝗮 𝗖𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻𝘀 Work efficiently with data structures. 🔹 List, Set, Map interfaces 🔹 ArrayList, LinkedList 🔹 HashMap, TreeMap 🔹 HashSet, TreeSet 🔹 Iterators & comparators 𝗘𝘅𝗰𝗲𝗽𝘁𝗶𝗼𝗻 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 Write robust and fault-tolerant applications. 🔹 Try-catch-finally 🔹 Checked vs unchecked exceptions 🔹 Custom exceptions 🔹 Best practices 𝗙𝗶𝗹𝗲 𝗜/𝗢 & 𝗦𝗲𝗿𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻 Handle data storage and transfer. 🔹 File reading/writing 🔹 Buffered streams 🔹 Object serialization 🔹 NIO (New I/O) 𝗠𝘂𝗹𝘁𝗶𝘁𝗵𝗿𝗲𝗮𝗱𝗶𝗻𝗴 & 𝗖𝗼𝗻𝗰𝘂𝗿𝗿𝗲𝗻𝗰𝘆 Build high-performance applications. 🔹 Threads & Runnable 🔹 Synchronization & locks 🔹 Executors & thread pools 🔹 CompletableFuture 🔹 Concurrent collections 𝗝𝗮𝘃𝗮 𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝗮𝗹 𝗣𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 Modern Java (Java 8 ) features. 🔹 Lambda expressions 🔹 Streams API 🔹 Functional interfaces 🔹 Optional class 🔹 Method references 𝗝𝗮𝘃𝗮 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸𝘀 Build scalable applications faster. 🔹 Spring Framework 🔹 Spring Boot 🔹 Spring MVC 🔹 Hibernate / JPA 🔹 Micronaut / Quarkus 𝗗𝗮𝘁𝗮𝗯𝗮𝘀𝗲𝘀 & 𝗣𝗲𝗿𝘀𝗶𝘀𝘁𝗲𝗻𝗰𝗲 Store and manage application data. 🔹 JDBC 🔹 SQL (MySQL, PostgreSQL) 🔹 ORM (Hibernate) 🔹 Transactions & connection pooling 𝗕𝘂𝗶𝗹𝗱 𝗧𝗼𝗼𝗹𝘀 & 𝗗𝗲𝗽𝗲𝗻𝗱𝗲𝗻𝗰𝘆 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁 Manage and build projects efficiently. 🔹 Maven 🔹 Gradle 🔹 Project structure 🔹 Dependency management 𝗧𝗲𝘀𝘁𝗶𝗻𝗴 Ensure code quality and reliability. 🔹 JUnit 🔹 Mockito 🔹 Integration testing 🔹 Test-driven development (TDD) 𝗗𝗲𝘃𝗢𝗽𝘀 & 𝗗𝗲𝗽𝗹𝗼𝘆𝗺𝗲𝗻𝘁 Take your Java apps to production. 🔹 Docker & containerization 🔹 CI/CD pipelines 🔹 Cloud deployment (AWS, Azure) 🔹 Monitoring & logging 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝗲𝘀𝗶𝗴𝗻 𝗳𝗼𝗿 𝗝𝗮𝘃𝗮 Design scalable backend systems. 🔹 REST APIs & microservices 🔹 Caching (Redis) 🔹 Message queues (Kafka, RabbitMQ) 🔹 Load balancing & scaling 𝗥𝗲𝗮𝗹-𝗪𝗼𝗿𝗹𝗱 𝗣𝗿𝗼𝗷𝗲𝗰𝘁𝘀 Apply your knowledge practically. 🔹 RESTful API with Spring Boot 🔹 E-commerce backend system 🔹 Authentication system (JWT) 🔹 Microservices architecture project 🔹 Banking or payment system Mastering this roadmap will take you from beginner to a professional Java developer capable of building scalable, production-ready applications.

Also tried to solve leetcode potd (hard), initially went with a greedy approach checking nearest factory in both directions using treeset but it failed After a hint switched to a simpler recursion dp approach and it got accepted Now next have to learn frontend logging and

𝗝𝗮𝘃𝗮 𝗥𝗼𝗮𝗱𝗺𝗮𝗽 𝟮𝟬𝟮𝟲 𝗝𝗮𝘃𝗮 𝗙𝘂𝗻𝗱𝗮𝗺𝗲𝗻𝘁𝗮𝗹𝘀 Start with the core building blocks of Java programming. 🔹 Syntax & structure 🔹 Variables, data types, operators 🔹 Control flow (if/else, loops, switch) 🔹 Functions / methods 🔹 Arrays & strings 𝗢𝗯𝗷𝗲𝗰𝘁-𝗢𝗿𝗶𝗲𝗻𝘁𝗲𝗱 𝗣𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 (𝗢𝗢𝗣) Java is built on OOP — master it deeply. 🔹 Classes & objects 🔹 Encapsulation, inheritance, polymorphism, abstraction 🔹 Interfaces & abstract classes 🔹 Constructors & method overloading 🔹 Access modifiers 𝗝𝗮𝘃𝗮 𝗖𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻𝘀 Work efficiently with data structures. 🔹 List, Set, Map interfaces 🔹 ArrayList, LinkedList 🔹 HashMap, TreeMap 🔹 HashSet, TreeSet 🔹 Iterators & comparators 𝗘𝘅𝗰𝗲𝗽𝘁𝗶𝗼𝗻 𝗛𝗮𝗻𝗱𝗹𝗶𝗻𝗴 Write robust and fault-tolerant applications. 🔹 Try-catch-finally 🔹 Checked vs unchecked exceptions 🔹 Custom exceptions 🔹 Best practices 𝗙𝗶𝗹𝗲 𝗜/𝗢 & 𝗦𝗲𝗿𝗶𝗮𝗹𝗶𝘇𝗮𝘁𝗶𝗼𝗻 Handle data storage and transfer. 🔹 File reading/writing 🔹 Buffered streams 🔹 Object serialization 🔹 NIO (New I/O) 𝗠𝘂𝗹𝘁𝗶𝘁𝗵𝗿𝗲𝗮𝗱𝗶𝗻𝗴 & 𝗖𝗼𝗻𝗰𝘂𝗿𝗿𝗲𝗻𝗰𝘆 Build high-performance applications. 🔹 Threads & Runnable 🔹 Synchronization & locks 🔹 Executors & thread pools 🔹 CompletableFuture 🔹 Concurrent collections 𝗝𝗮𝘃𝗮 𝗙𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝗮𝗹 𝗣𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 Modern Java (Java 8 ) features. 🔹 Lambda expressions 🔹 Streams API 🔹 Functional interfaces 🔹 Optional class 🔹 Method references 𝗝𝗮𝘃𝗮 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸𝘀 Build scalable applications faster. 🔹 Spring Framework 🔹 Spring Boot 🔹 Spring MVC 🔹 Hibernate / JPA 🔹 Micronaut / Quarkus 𝗗𝗮𝘁𝗮𝗯𝗮𝘀𝗲𝘀 & 𝗣𝗲𝗿𝘀𝗶𝘀𝘁𝗲𝗻𝗰𝗲 Store and manage application data. 🔹 JDBC 🔹 SQL (MySQL, PostgreSQL) 🔹 ORM (Hibernate) 🔹 Transactions & connection pooling 𝗕𝘂𝗶𝗹𝗱 𝗧𝗼𝗼𝗹𝘀 & 𝗗𝗲𝗽𝗲𝗻𝗱𝗲𝗻𝗰𝘆 𝗠𝗮𝗻𝗮𝗴𝗲𝗺𝗲𝗻𝘁 Manage and build projects efficiently. 🔹 Maven 🔹 Gradle 🔹 Project structure 🔹 Dependency management 𝗧𝗲𝘀𝘁𝗶𝗻𝗴 Ensure code quality and reliability. 🔹 JUnit 🔹 Mockito 🔹 Integration testing 🔹 Test-driven development (TDD) 𝗗𝗲𝘃𝗢𝗽𝘀 & 𝗗𝗲𝗽𝗹𝗼𝘆𝗺𝗲𝗻𝘁 Take your Java apps to production. 🔹 Docker & containerization 🔹 CI/CD pipelines 🔹 Cloud deployment (AWS, Azure) 🔹 Monitoring & logging 𝗦𝘆𝘀𝘁𝗲𝗺 𝗗𝗲𝘀𝗶𝗴𝗻 𝗳𝗼𝗿 𝗝𝗮𝘃𝗮 Design scalable backend systems. 🔹 REST APIs & microservices 🔹 Caching (Redis) 🔹 Message queues (Kafka, RabbitMQ) 🔹 Load balancing & scaling 𝗥𝗲𝗮𝗹-𝗪𝗼𝗿𝗹𝗱 𝗣𝗿𝗼𝗷𝗲𝗰𝘁𝘀 Apply your knowledge practically. 🔹 RESTful API with Spring Boot 🔹 E-commerce backend system 🔹 Authentication system (JWT) 🔹 Microservices architecture project 🔹 Banking or payment system Mastering this roadmap will take you from beginner to a professional Java developer capable of building scalable, production-ready applications. Get the complete Java Handbook here: 👉 codewithdhanian.gumroad.com/…

🚀 Day 34 Java: Sets & Maps! Set Interface-Inherits all core funtionality. TreeSet-NavigableSet and SortedSet for ordering. Internal Storage-Sets internally use a HM. ConcurrentHashMap-Preferred Hashtable for multi-threaded environments. Specialized Maps-Covered EnumMap.

Today’s Progress: Learned about Map Tiles, including Vector Tiles vs Raster Tiles Set up Leaflet for map initialization Debugged issues related to Raster / GeoTIFF layers and made UI improvements in work Solved LeetCode POTD: Part 1 (Easy) Part 2 (Medium) using TreeSet

Day 36 & 37 of my Java journey 📘 Comparable • Custom sorting using compareTo() • 0 return can be dangerous in TreeSet/TreeMap 📘 Lambda Functional Interface • Short & clean code • Works with single abstract method Thanks @rohit_negi9 & @adityatandon02 #Java #Coding

#geekstreak60 #npci Day : 51/60 POTD : Intersection of Two Sorted Arrays Approach: Solved independently using Two Pointers. Initially used a TreeSet, then optimized to solve without extra space.

Day 33 of my Java journey 📘 Collection Framework (Set & Map) • Hash collisions & chaining • HashSet / HashMap • LinkedHashSet / LinkedHashMap (order maintained) • TreeSet / TreeMap (sorted) Thanks @rohit_negi9 & @adityatandon02 #Java #Coding #DSA #Programming #Learning

#Day29: Java Collection Framework unifies data structures via Iterable > Collection (List, Set, Queue) and Map, optimizing storage. implementations: ArrayList, LinkedList , HashSet/HashMap (O(1) hashing), TreeSet/TreeMap (sorted O(log n)), Queue/Deque (FIFO).