Daily LeetCode Challenge #20 | Valid Parentheses | Java | Stack | 01-10-2026

🚀 Daily LeetCode Challenge #20 – Valid Parentheses Welcome to another Daily LeetCode Challenge by SkillSpring! 🌱 📅 Date: 01-10-2026 💻 Language: Java 🧩 Problem: #20 – Valid Parentheses 📚 Topic: Stack In this video, we solve the classic Valid Parentheses problem using a Stack and understand the logic step by step. 🔢 Examples Example 1: Input: s = "()" Output: true Example 2: Input: s = "()[]{}" Output: true Example 3: Input: s = "(]" Output: false 💡 Key Idea We use a Stack to keep track of opening brackets. ( → expect ) [ → expect ] { → expect } When a closing bracket appears, check whether it matches the top of the stack. At the end, the stack must be empty. 📚 What You'll Learn ✅ Understand the Valid Parentheses problem ✅ Why a Stack is useful ✅ Matching opening and closing brackets ✅ Handling (), [], and {} ✅ Detecting invalid parentheses ✅ Step-by-step dry run ✅ Java implementation ✅ Time & Space Complexity ⏱️ Time Complexity: O(N) 💾 Space Complexity: O(N) 🔥 One LeetCode problem every day → stronger DSA skills every day! 👍 Like the video 💬 Comment your approach 🔔 Subscribe to SkillSpring for Java, DSA & Daily LeetCode challenges. #LeetCode #LeetCode20 #ValidParentheses #Java #DSA #Stack #DataStructures #Coding #Programming #SkillSpring #DailyLeetCode #01October2026 #LeetCodeChallenge #leetcodeproblemoftheday #20 #leetcodepotd #leetcode