LeetCode 1622 Fancy Sequence | Hard DSA Problem Explained | Data Structure Design скачать в хорошем качестве

LeetCode 1622 Fancy Sequence | Hard DSA Problem Explained | Data Structure Design

🚀 LeetCode 1622 – Fancy Sequence | Design Data Structure Interview Problem (Java) In this video, we solve LeetCode Problem 1622: Fancy Sequence, a Hard Data Structure Design problem that frequently appears in coding interviews and system design style DSA questions. This problem teaches an important concept used in advanced DSA problems: Lazy Updates + Mathematical Transformation for Efficient Data Structure Design Instead of updating every element in the sequence repeatedly, we learn how to optimize operations using mathematical transformations so each operation runs efficiently. We will break the problem down step-by-step, understand the core idea behind designing a custom data structure, and implement a clean Java solution used in coding interviews. 🧠 Problem Summary You need to design a data structure called Fancy that supports the following operations: • append(val) → Add an integer to the end of the sequence • addAll(inc) → Increase all existing elements by inc • multAll(m) → Multiply all elements by m • getIndex(idx) → Return the value at index idx The result must be returned modulo 10⁹ + 7. If the index is out of bounds, return -1. This problem tests your ability to design efficient APIs and avoid brute force updates. 📌 Example Input Fancy append(2) addAll(3) append(7) multAll(2) getIndex(0) Output 10 Explanation Sequence transformation: [2] [5] [5,7] [10,14] getIndex(0) → 10 🔍 Key Idea This problem teaches an important interview concept: Data Structure Design + Mathematical Optimization Instead of updating the entire array for every operation, we use: 1️⃣ Lazy transformation technique 2️⃣ Multiplication and addition tracking 3️⃣ Mathematical reverse transformation when appending values This allows us to handle all operations efficiently. This pattern is commonly asked in: • FAANG coding interviews • Data Structure design questions • Advanced DSA interview problems ⏱ Complexity Time Complexity O(1) per operation Space Complexity O(n) Where n = number of appended elements 📢 Join Our WhatsApp Channel Get daily LeetCode problems, DSA interview tips, and coding interview preparation resources 👉 https://whatsapp.com/channel/0029Vb80... 💻 Code & Notes Repository 🔗 All LeetCode Solutions Repository https://github.com/Gopalkushwaha1/Lee... 🔗 AlgoDiary Interview Notes + Structured Code https://github.com/Gopalkushwaha1/Alg... 🔗 Direct Problem Folder (1622) https://github.com/Gopalkushwaha1/Alg... 🔗 Java Solution File https://github.com/Gopalkushwaha1/Alg... 🔗 C++ Solution File https://github.com/Gopalkushwaha1/Alg... 🔗 Python Solution File https://github.com/Gopalkushwaha1/Alg... 🔥 What you will learn in this video • Fancy Sequence problem explanation • How to design a custom Data Structure • Handling multiple operations efficiently • Optimizing append, addAll, and multAll operations • Writing clean Java, C++, and Python code • Understanding advanced DSA interview patterns • Time and Space complexity analysis 🎯 Who should watch this video? • Students preparing for coding interviews • Developers practicing LeetCode Hard problems • Beginners learning Data Structure Design • Anyone improving DSA problem solving skills leetcode 1622 leetcode 1622 solution fancy sequence leetcode leetcode hard problem leetcode hard dsa solution design data structure leetcode leetcode fancy sequence java leetcode fancy sequence cpp leetcode fancy sequence python data structures and algorithms coding interview preparation leetcode problem solving software engineer interview preparation