README.md

Stack Data-Structures and Algorithms

01. The Stack data Structure

Stack Data Structure
Stack is FILO(First In Last Out) or LIFO(Last In First Out) Data structure

   | D |
   | C |
   | B |
   | A |
   -----

Example:
This is stack

        |   |
        -----

When you push() an element 'A' to stack
stack will look like

                    | A |
                    -----

Now if you push() some more elements, it will place one above one
final stack:

            | D |
            | C |
            | B |
            | A |
            -----

When you pop() the element from stack, it will pop() from top of the stack or the recent pushed element

            | C |
            | B |
            | A |
            -----

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02. The Stack data Structure : Understanding Stack

The Stack data Structure : Understanding Stack
deque is using Doubly Linked List data structure to store the element.

Stack is FILO(First In Last Out) or LIFO(Last In First Out) Data structure

   | D |
   | C |
   | B |
   | A |
   -----

Example:
This is stack

        |   |
        -----

When you push() an element 'A' to stack
stack will look like

                    | A |
                    -----

Now if you push() some more elements, it will place one above one
final stack:

            | D |
            | C |
            | B |
            | A |
            -----

When you pop() the element from stack, it will pop() from top of the stack or the recent pushed element

            | C |
            | B |
            | A |
            -----

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03. Determine if parenthesis are balanced

Leetcode Problem URL

Determine if parenthesis are balanced
Use a stack to check whether or not a string has
balanced usage of parenthesis.

Example:
    (), ()(), (({{[]}})) <== Balanced.
    ((),  {{{)}], [][]]] <== Not Balanced.

Balanced Example: {[]}

Non-Balanced Example: (()

Non-Balanced Example: ]]

Problem Statement :
Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets.
Open brackets must be closed in the correct order.
Every close bracket has a corresponding open bracket of the same type.

Example 1:
Input: s = "()"
Output: true

Example 2:
Input: s = "()[]{}"
Output: true

Example 3:
Input: s = "(]"
Output: false

04. Convert integer to binary

Convert integer to binary
Use a stack data structure to convert integer values to binary.

Example : 242

242 / 2 = 121 -> 0    # 0 is a remainder as number is even
121 / 2 = 60  -> 1    # 1 is a remainder as number is odd
60 / 2  = 30  -> 0    # 0 is a remainder as number is even
30 / 2  = 15  -> 0    # 0 is a remainder as number is even
15 / 2  = 7   -> 1    # 1 is a remainder as number is odd
7 / 2   = 3   -> 1    # 1 is a remainder as number is odd
3 / 2   = 1   -> 1    # 1 is a remainder as number is odd
1 / 2   = 0   -> 1    # 1 is a remainder as number is odd

11110010 is the binary number of integer 242

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05. The Stack data Structure : Reverse String

The Stack data Structure : Reverse String
It will return the reverse string from given string.

Example:
        str = "You can do it."
    output:
            .ti od nac uoY

First push() all the characters from str to stack.

declare an empty string variable

Now, pop() characters one by one and add it to an empty string variable

return empty string variable

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