🚀 LeetCode #118 – Pascal’s Triangle | Java Solution Today I solved the classic Pascal’s Triangle problem — a great exercise to strengthen understanding of lists, iteration, and dynamic building of data structures. 📌 Problem Summary Given an integer numRows, generate the first numRows of Pascal’s Triangle. Each element is the sum of the two elements directly above it. 💡 Approach I Used Start with the first row [1] For each new row: First and last elements are always 1 Middle elements = sum of previous row elements Build row by row using a loop 🧠 Key Learning Handling nested lists (List<List<Integer>>) Using previous computation to build the next (Dynamic Thinking) Clean iteration logic 💻 Java Code Snippet for(int i = 1; i < numRows; i++){ List<Integer> prev = resultList.get(i - 1); List<Integer> curr = new ArrayList<>(); curr.add(1); for(int j = 1; j < i; j++){ curr.add(prev.get(j - 1) + prev.get(j)); } curr.add(1); resultList.add(curr); } 📊 Output Example (numRows = 5): [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] Happy Coding 😊; #LeetCode #Java #DSA #CodingJourney #ProblemSolving #SoftwareDevelopment #100DaysOfCode
Pascal's Triangle Java Solution LeetCode
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♻️ Ever wondered how Java manages memory automatically? Java uses Garbage Collection (GC) to clean up unused objects — so developers don’t have to manually manage memory. Here’s the core idea in simple terms 👇 🧠 Java works on reachability It starts from GC Roots: • Variables in use • Static data • Running threads Then checks: ✅ Reachable → stays in memory ❌ Not reachable → gets removed 💡 Even objects referencing each other can be cleaned if nothing is using them. 🔍 Different types of Garbage Collectors in Java: 1️⃣ Serial GC • Single-threaded • Best for small applications 2️⃣ Parallel GC • Uses multiple threads • Focuses on high throughput 3️⃣ CMS (Concurrent Mark Sweep) • Runs alongside application • Reduces pause time (now deprecated) 4️⃣ G1 (Garbage First) • Splits heap into regions • Balanced performance + low pause time 5️⃣ ZGC • Ultra-low latency GC • Designed for large-scale applications ⚠️ One important thing: If an object is still referenced (even accidentally), it won’t be cleaned → which can lead to memory issues. 📌 In short: Java automatically removes unused objects by checking whether they are still reachable — using different GC strategies optimized for performance and latency. #Java #Programming #JVM #GarbageCollection #SoftwareDevelopment #TechConcepts
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🚀 Arrays in Java (Quick Guide) An Array is one of the most important data structures in Java. It stores multiple values of the same data type in a fixed-size container. ✅ Key Features of Arrays Stores elements in contiguous memory Size is fixed once declared Supports index-based access Faster retrieval using index (O(1)) 📌 Example int[] arr = {10, 20, 30, 40}; System.out.println(arr[0]); // Output: 10 🔥 Advantages ✔ Fast access using index ✔ Easy to iterate ✔ Memory efficient for fixed data ⚠ Limitations ❌ Size cannot grow dynamically ❌ Insertion/deletion in middle is costly (O(n)) 💡 When to Use Arrays? 👉 When the size is known in advance 👉 When you need fast indexing 👉 For performance-critical applications Arrays are the foundation for many advanced structures like ArrayList, Heap, Stack, and more. hashtag #Java #Arrays #DSA #Programming #InterviewPreparation
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🚀 Day 3 – Why String is Immutable in Java (and why it matters) One question I explored today: Why are "String" objects immutable in Java? String s = "hello"; s.concat(" world"); System.out.println(s); // still "hello" 👉 Instead of modifying the existing object, Java creates a new String But why was it designed this way? ✔ Security – Strings are widely used in sensitive areas (like class loading, file paths, network connections). Immutability prevents accidental or malicious changes. ✔ Performance (String Pool) – Since Strings don’t change, they can be safely reused from the pool, saving memory. ✔ Thread Safety – No synchronization needed, multiple threads can use the same String safely. 💡 This also explains why classes like "StringBuilder" and "StringBuffer" exist—for mutable operations when performance matters. Small design decision, but huge impact on how Java applications behave internally. #Java #BackendDevelopment #JavaInternals #LearningInPublic #SoftwareEngineering
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🚀 **Day 4/30 – LeetCode Java Challenge** Today’s problem pushed me to think beyond basic comparisons and focus on **pattern-based validation**. Worked on a string problem where the key insight was separating characters based on **even and odd indices**, then comparing frequency distributions instead of direct string matching. 📊 **Result:** ✔️ Accepted (752/752 test cases) ⚡ Runtime: 5 ms (Beats 93.81%) 💾 Memory: Efficient (Beats 86.60%) 💡 **What actually mattered today:** * Brute force thinking won’t scale — pattern recognition does * Breaking a problem into smaller logical groups simplifies everything * Frequency arrays can outperform more complex data structures when used correctly Let’s be real: This wasn’t a hard problem, but the approach matters. If you miss the pattern, you overcomplicate it. If you see it early, the solution becomes clean and efficient. Day 4 done. Still building consistency, still sharpening fundamentals. Archana J E Bavani k Deepika Kannan Divya Suresh Hari priya B Devipriya R Harini B Bhavya B Kezia H Vaishnavi Janaki #LeetCode #Java #DSA #ProblemSolving #Consistency #30DaysOfCode
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Topic of the day String? Why String is Immutable? 👉 In Java, a String is immutable, which means once it is created, its value cannot be changed. Example: String s = "Hello"; s.concat(" World"); 👉 You might expect: "Hello World" 👉 But actual output: "Hello" Because concat() creates a new object, instead of modifying the existing one. 🔍 Why did Java designers make String immutable? ✔️ Security – Strings are used in sensitive areas (like DB connections, file paths, network URLs) ✔️ Thread Safety – No need for synchronization (safe in multithreading) ✔️ Performance – Enables String Pool (memory optimization) ✔️ Caching – Hashcode can be cached (used in HashMap) If you are doing multiple string modifications, prefer: 👉 StringBuilder (faster, not thread-safe) 👉 StringBuffer (thread-safe) #Java #JavaConcepts #InterviewPreparation #Programming #Developers #Programming #Development #Coding
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#TapAcademy #Java #Fullstackdeveloment #Strings Strings in Java are used to store and handle text data. They are created using double quotes. For example, String text = "Hello, World!". Java offers many useful string methods, such as concat(), substring(), and toUpperCase(). You can compare, join, and format strings with these built-in methods. Strings are commonly used for managing text input, output, and data processing in programs.
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🔥 Day 21: Synchronization in Java A crucial concept in multithreading to avoid data inconsistency 👇 🔹 What is Synchronization? 👉 Definition: Synchronization is a mechanism to control access of multiple threads to shared resources. 🔹 Why Do We Need It? 👉 Without synchronization: Multiple threads modify data ❌ Results become inconsistent ❌ 👉 With synchronization: Only one thread accesses at a time ✅ Data remains correct ✅ 🔹 Simple Example (Without Synchronization) class Counter { int count = 0; void increment() { count++; } } 👉 Problem: Multiple threads → wrong count ⚠️ 🔹 With Synchronization class Counter { int count = 0; synchronized void increment() { count++; } } 👉 Now: ✔ One thread at a time ✔ Correct result 🔹 Types of Synchronization 1️⃣ Method Level synchronized void method() { } 2️⃣ Block Level synchronized(this) { // critical section } 3️⃣ Static Synchronization static synchronized void method() { } 🔹 Key Points ✔ Prevents race conditions ✔ Uses intrinsic lock (monitor) ✔ Slows performance slightly (due to locking) 🔹 When to Use? ✔ Shared variables ✔ Multi-threaded environment ✔ Critical sections 💡 Pro Tip: Use synchronization only where needed — too much can reduce performance ⚡ 📌 Final Thought: "Synchronization ensures safety, but balance it with performance." #Java #Multithreading #Synchronization #ThreadSafety #Programming #JavaDeveloper #Coding #InterviewPrep #Day21
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Day 7 of #100DaysOfCode — Java is getting interesting ☕ Today I explored the Java Collections Framework. Before this, I was using arrays for everything. But arrays have one limitation — fixed size. 👉 What if we need to add more data later? That’s where Collections come in. 🔹 Key Learnings: ArrayList grows dynamically — no size worries Easy operations: add(), remove(), get(), size() More flexible than arrays 🔹 Iterator (Game changer) A clean way to loop through collections: hasNext() → checks next element next() → returns next element remove() → safely removes element 🔹 Concept that clicked today: Iterable → Collection → List → ArrayList This small hierarchy made everything much clearer. ⚡ Array vs ArrayList Array → fixed size ArrayList → dynamic size Array → stores primitives ArrayList → stores objects Still exploring: Set, Map, Queue next 🔥 Consistency is the only plan. Showing up every day 💪 If you’re also learning Java or working with Collections — let’s connect 🤝 #Java #Collections #ArrayList #100DaysOfCode #JavaDeveloper #LearningInPublic
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🚀 Java 25 is bringing some seriously exciting improvements I’ve published a blog post where I break down the key features you should know about in Java 25👇 🔍 Here’s a quick preview of what’s inside: 🧩 Primitive Types in Patterns (JEP 507) Pattern matching gets even more powerful by supporting primitive types - making your code more expressive and reducing boilerplate. 📦 Module Import Declarations (JEP 511) Simplifies module usage with cleaner import syntax, helping you write more readable and maintainable modular applications. ⚡ Compact Source Files & Instance Main (JEP 512) A big win for simplicity! You can write shorter programs without the usual ceremony - perfect for beginners and quick scripts. 🛠️ Flexible Constructor Bodies (JEP 513) Constructors become more flexible, giving developers better control over initialization logic and improving code clarity. 🔒 Scoped Values (JEP 506) A modern alternative to thread-local variables, designed for safer and more efficient data sharing in concurrent applications. 🧱 Stable Values (JEP 502) Helps manage immutable data more efficiently, improving performance and reliability in multi-threaded environments. 🧠 Compact Object Headers (JEP 519) Optimizes memory usage by reducing object header size - a huge benefit for high-performance and memory-sensitive applications. 🚄 Vector API (JEP 508) Enables developers to leverage modern CPU instructions for parallel computations - boosting performance for data-heavy workloads. 💡 Whether you're focused on performance, cleaner syntax, or modern concurrency, Java 25 delivers meaningful improvements across the board. 👇 Curious to learn more? Check the link of full article in my comment. #Java #Java25 #SoftwareDevelopment #Programming #Developers #Tech #JVM #Coding #Performance #Concurrency
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🔥 Day 16: Method References (:: operator) in Java A powerful feature introduced in Java 8 that makes your code cleaner and more readable 👇 🔹 What is Method Reference? 👉 Definition: A shorter way to refer to a method using :: instead of writing a lambda expression. 🔹 Why Use It? ✔ Reduces boilerplate code ✔ Improves readability ✔ Works perfectly with Streams & Functional Interfaces 🔹 Lambda vs Method Reference 👉 Using Lambda: list.forEach(x -> System.out.println(x)); 👉 Using Method Reference: list.forEach(System.out::println); ✨ Cleaner & simpler! 🔹 Types of Method References 1️⃣ Static Method Reference ClassName::staticMethod 2️⃣ Instance Method (of object) object::instanceMethod 3️⃣ Instance Method (of class) ClassName::instanceMethod 4️⃣ Constructor Reference ClassName::new 🔹 Examples ✔ Static: Math::max ✔ Instance: System.out::println ✔ Constructor: ArrayList::new 🔹 When to Use? ✔ When lambda just calls an existing method ✔ To make code shorter and cleaner ✔ With Streams and Functional Interfaces 💡 Pro Tip: If your lambda looks like 👉 (x) -> method(x) You can replace it with 👉 Class::method 📌 Final Thought: "Method Reference = Cleaner Lambda" #Java #MethodReference #Java8 #Streams #Programming #JavaDeveloper #Coding #InterviewPrep #Day16
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