Add stacks data structure

[Shubhayu-Das]

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• [ ] Is this a bug fix?
• [x] Is this an enhancement?
• [x] Is this a feature request?

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Stacks are often very useful in competitive programming owing to their LIFO property. Add a data structure with the following function:

Push(data) - Insert data into the stack.

Pop() - Delete the topmost element from the stack.

Top() - Return the topmost element(HEAD) of the stack without popping it.

copy() - Returns a copy passed stack object. Example: Stack1 = [ 3, 2, 1]; let Stack2 = copy(Stack1); //Stack2 also stores [3, 2, 1] now

isEmpty() - returns true if the stack has no elements in it. Returns false otherwise.

printStack() - prints all the elements of the stack. (In LIFO Order only.)

Refer to: https://www.geeksforgeeks.org/implementation-stack-javascript/

[fave77]

@sateslayer will you be working on this?

[Shubhayu-Das]

Yes I will work on it.

[fave77]

@sateslayer Implement it like PriorityQueue