Скачать или смотреть Cracking LeetCode #20 — Valid Parenthesis: Stack Attack — use a stack, beat mismatches, O(n) time.

LeetCode 20 Valid Parentheses Solution | Stack Approach Explained
In this video, we solve LeetCode Problem #20: Valid Parentheses step by step using the stack data structure. This is one of the most popular LeetCode easy problems and is frequently asked in coding interviews at top tech companies.
You’ll learn:
✅ How to use a stack to validate parentheses (()[]{})
✅ Step-by-step walkthrough with examples of valid and invalid strings
✅ Edge cases that trip up beginners (mismatched or odd-length inputs)
✅ Time Complexity: O(n) and Space Complexity: O(n)
✅ Why this problem is a classic coding interview question
By the end, you’ll be confident in solving string validation problems using stacks and ready to ace this common interview coding challenge.
00:30 – Understanding the problemt Statement
01:15 – Brute Force Approach
02:30 – Code walkthrough in python
06:00 – Optimal approach using Stack (LIFO)
07:30 – Code walkthrough in python