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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=aHR0cHM6Ly9zY29udGVudC1saHI2LTEuY2RuaW5zdGFncmFtLmNvbS92L3Q1MS44Mjc4Ny0xNS82NDE5Nzg1ODBfMTc4NzY0MDQ0NjE1MjA3NTNfNDgxNTkyMzA0MjE4OTg2MjAyNl9uLmpwZz9zdHA9ZHN0LWpwZ19lMzVfczY0MHg2NDBfdHQ2Jl9uY19jYXQ9MTEwJmNjYj03LTUmX25jX3NpZD0xOGRlNzQmZWZnPWV5SmxabWRmZEdGbklqb2lRMHhKVUZNdVltVnpkRjlwYldGblpWOTFjbXhuWlc0dVF6TWlmUSUzRCUzRCZfbmNfb2hjPWpLbVgxQWlPdnpRUTdrTnZ3RUpNX0dkJl9uY19vYz1BZHBZRFVxWkVCSU5IX3lfb3hac0lEZl9zZzVOcGFrRkJUR0JWdG5XYjBNWmtKNmhFM0o1QVJIU3ZWaWhnb25qb0VJJl9uY196dD0yMyZfbmNfaHQ9c2NvbnRlbnQtbGhyNi0xLmNkbmluc3RhZ3JhbS5jb20mX25jX2dpZD1yZzZnS1BfSGxuTXNpQjYzQkxtSzRnJl9uY19zcz03YTMwZiZvaD0wMF9BZnluWWVYcXNScFp0Sk1SN2xBSjh6RGJBY2xCX0V4d0hzQzJKbi1yaWtfUFdRJm9lPTY5Q0RGOTQw)
![#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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)