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NEValid Parentheses 🔥 The Stack Trick Every Coding Interview Uses
This is one of the most asked coding interview questions.
Given a string containing (), {}, [], you must determine if the parentheses are valid and correctly ordered.
The trick interviewers expect is using a Stack.
✔ Push opening brackets
✔ When you see a closing bracket, check the top of the stack
✔ If it matches → pop it
✔ If not → invalid
If the stack is empty at the end → the string is valid.
⏱ Time Complexity: O(n)
📦 Space Complexity: O(n)
This problem teaches a fundamental stack pattern used in many coding interviews.
📌 Save this reel for your DSA preparation
💬 Comment “STACK” if you want more stack interview problems.
#leetcode
#datastructures
#codinginterview
#algorithms
#python
@next.tech12
![#Valid Parentheses Reel by @codewithupasana - LeetCode 20: Valid Parentheses
You're given a string of brackets - (), {}, []
Your job? Check if it's valid, meaning:
✅ Every opening has a closing
✅](https://image.pictame.com/img/514041031_17914065933140444_3026080617525550810_n.jpg?hash=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)
![#Valid Parentheses Reel by @rakeshcodeburner (verified account) - Valid Parentheses - Stack Pattern (LeetCode 20)
Given a string containing (), {}, and [], check if the parentheses are valid.
📌 Key idea:
Push ope](https://image.pictame.com/img/641978580_17876404461520753_4815923042189862026_n.jpg?hash=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)
![#Valid Parentheses Reel by @bytesizeddev - 20. Valid Parentheses
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
Solut](https://image.pictame.com/img/498158675_662316229905420_4906555074293463686_n.jpg?hash=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)
![#Valid Parentheses Reel by @itssiddharthsinghh - Day 88/100: Today I solved 4 questions based on strings:
1) Buddy Strings [easy]
2) Additive Number [medium]
3) Top K Frequent Words [medium]
4) Minim](https://image.pictame.com/img/503291249_3590433787758656_3188990337696516103_n.jpg?hash=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)