Leetcode 567 Permutation in String | Java | Pattern 3 : Sliding Window скачать в хорошем качестве

Leetcode 567 Permutation in String | Java | Pattern 3 : Sliding Window

In this video, we solve Permutation in String (LeetCode 567) using Java. The problem asks us to determine whether any permutation of a given string s1 exists as a substring in another string s2. We start by understanding the brute force approach where we generate all permutations of s1 and check whether any of them appear in s2. While this approach explains the problem clearly, it is highly inefficient because permutation generation has factorial complexity. To optimize the solution, we use the Sliding Window technique combined with character frequency counting. Since all permutations of a string have identical character frequencies, we simply need to check whether any substring in s2 has the same frequency distribution as s1. By maintaining a sliding window of size s1.length() and updating frequency arrays dynamically, we can solve this problem in O(n) time. In this tutorial you will learn: • How to detect permutations using character frequencies • The brute force idea behind permutation checking • The Sliding Window algorithm pattern • Efficient frequency array comparison • Clean and interview-ready Java implementation This problem is very important for coding interview preparation because it teaches how to combine Sliding Window with hashing techniques for string problems. Topics covered: Java DSA, Sliding Window Pattern, String Algorithms, Coding Interview Preparation. #leetcode #java #datastructures #codinginterview #slidingwindow #dsa