Amazon Coding Interview Question - Min Stack (LeetCode)

Here is a step by step explanation of a stack based problem asked at many top tech companies!

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The problem "Min Stack" has been a popular interview question for a long time now asked at top tech companies including Amazon, Google, Bloomberg, and Apple. For this problem, we must extend the functionality of a stack (LIFO) and allow for constant time lookup for the minimum element in our stack.

A common pitfall for this problem is to keep track of the minimum element with a single variable; however, that will not work in the scenario we pop our minimum element. What we must do is create a second stack that keeps track of our minimum every time we add a new element into our original stack.

The time complexity is constant time O(1) and our space complexity is O(N) where N is the number of elements in our stacks.

[NextInterviewPrep]

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[ashwinhariharan]

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[TP-xtsv]

I love you so much since your explanation always helps me A LOT.

[chaitanyakarthik]

this was nice explanation bro, really loved it!!

[ChandraShekhar-bycd]

@
Michael Muinos Thanks a lot for such a great explanation . Could you please upload more frequent videos on leetocode and DSA, it is really very informative to get the concepts from you!

[priyanshrastogi]

You explain really good 👍. Keep it up..
Please solve Sliding window median, Minimum falling path sum. If you have time..

[deepakmarneni]

Awesome.. great explanation.. waiting for more video's.

[yitingg]

Thanks a lot for another great video!! I am waiting for more each day. How do you come up with this solution? It's easy to implement but hard to come up with.

[vinoddiwan]

need to modify code because empty stack gives error now.

[rchukkapalli]

Do we really need to add the same value multiple times? can we just check the "peek()" and if it is less, then we can add right? great explanation and thank you for the videos.

[bhanugupta]

Recently i gave an interview the interviewer ask the same question but he also wants constant space Complexity means without using extra stack. can you please explains this also. Thank You