Added Min Stack program

[shuvojitss]

Pull Request for PyVerse 💡

Requesting to submit a pull request to the PyVerse repository.

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Issue Title

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Min Stack

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Info about the Related Issue

What's the goal of the project?
Design a Data Structure MinStack that supports all the stack operations like push(), pop(), and an additional operation getMin() which should return minimum element from the MinStack. All these operations of MinStack must have a time complexity of O(1).

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Name

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Shuvojit Samanta

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GitHub ID

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shuvojitss

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Email ID

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shuvojitsamanta15@gmail.com

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Identify Yourself

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GSSOC

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Closes

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Closes: #993

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Describe the Add-ons or Changes You've Made

Give a clear description of what you have added or modified.

Time Complexity Analysis

• push(value):

  • The push operation is O(1) because it only involves a few comparisons and calculations, followed by an append operation to the list (stack), which is constant time.

• pop():

  • The pop operation is O(1) because it only involves removing the top element from the stack and, if necessary, updating self.mini. List pop() for the last element in Python is O(1).

• top():

  • The top operation is O(1) since it only accesses the last element of the list (stack) and possibly performs one comparison.

• getmin():

  • The getmin operation is O(1) because it simply returns the current minimum value stored in self.mini.

Summary

Each operation in this MinStack implementation has a time complexity of O(1), making it efficient for stack operations with constant-time minimum retrieval.

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Type of Change

Select the type of change:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, local variables)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

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How Has This Been Tested?

Describe how your changes have been tested.
I have tested it in all python editors and its working. I am providing a sample input output to describe it.

Sample Input

stack.push(7)
stack.push(12)
stack.getMin()
stack.push(4)
stack.getMin()
stack.pop()
stack.getMin()
stack.push(6)
stack.getMin()
stack.pop()
stack.top()

Sample Output:

Element Pushed: 7
Element Pushed: 12
Minimum Element in the stack is: 7
Element Pushed: 4
Minimum Element in the stack is: 4
Element popped: 4
Minimum Element in the stack is: 7
Element Pushed: 6
Minimum Element in the stack is: 6
Element popped: 6
Top Most Element is: 12

• I have described my testing process.

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Checklist

Please confirm the following:

• My code follows the guidelines of this project.
• I have performed a self-review of my own code.
• I have commented my code, particularly wherever it was hard to understand.
• I have made corresponding changes to the documentation.
• My changes generate no new warnings.
• I have added things that prove my fix is effective or that my feature works.
• Any dependent changes have been merged and published in downstream modules.

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