fix(guide): simplify directory structure

guide/english/certifications/coding-interview-prep/data-structures/add-a-new-element-to-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Add a New Element to a Binary Search Tree
+---
+## Add a New Element to a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/add-a-new-element-to-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/add-elements-at-a-specific-index-in-a-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Add Elements at a Specific Index in a Linked List
+---
+## Add Elements at a Specific Index in a Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/add-elements-at-a-specific-index-in-a-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/adjacency-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Adjacency List
+---
+## Adjacency List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/adjacency-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/adjacency-matrix/index.md

@@ -0,0 +1,10 @@
+---
+title: Adjacency Matrix
+---
+## Adjacency Matrix
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/adjacency-matrix/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/breadth-first-search/index.md

@@ -0,0 +1,56 @@
+---
+title: Breadth-First Search
+---
+## Breadth-First Search
+
+Let's first define the `Tree` class to be used for the implementation of the Breadth First Search algorithm. 
+
+```python
+class Tree:
+  def __init__(self, x):
+    self.val = x
+    self.left = None
+    self.right = None
+```
+
+The breadth first search algorithm moves from one level to another starting from the root of the tree. We will make use of a `queue` for this. 
+
+```python
+
+def bfs(root_node):
+  queue = [root_node]
+  
+  while queue:
+    top_element = queue.pop()
+    print("Node processed: ",top_element)
+    
+    if top_element.left:
+      queue.append(top_element.left)
+
+    if top_element.right:
+      queue.append(top_element.right)
+``` 
+
+We can easily modify the above code to print the level of each node as well.
+
+```python
+
+def bfs(root_node):
+  queue = [(root_node, 0)]
+  
+  while queue:
+    top_element, level = queue.pop()
+    print("Node processed: {} at level {}".format(top_element, level))
+    
+    if top_element.left:
+      queue.append((top_element.left, level + 1))
+
+    if top_element.right:
+      queue.append((top_element.right, level + 1))
+```
+
+
+| Complexity   | Time | Space |
+| ----- | ------ | ------ | 
+| BFS |   n    |    n   |  
+

guide/english/certifications/coding-interview-prep/data-structures/check-if-an-element-is-present-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Check if an Element is Present in a Binary Search Tree
+---
+## Check if an Element is Present in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/check-if-an-element-is-present-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-circular-queue/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Circular Queue
+---
+## Create a Circular Queue
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-circular-queue/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-doubly-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Doubly Linked List
+---
+## Create a Doubly Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-doubly-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-hash-table/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Hash Table
+---
+## Create a Hash Table
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-hash-table/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-linked-list-class/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Linked List Class
+---
+## Create a Linked List Class
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-linked-list-class/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-map-data-structure/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Map Data Structure
+---
+## Create a Map Data Structure
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-map-data-structure/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-priority-queue-class/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Priority Queue Class
+---
+## Create a Priority Queue Class
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-priority-queue-class/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Queue Class
+---
+## Create a Queue Class
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-queue-class/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-set-class/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Set Class
+---
+## Create a Set Class
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-set-class/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-a-stack-class/index.md

@@ -0,0 +1,75 @@
+---
+title: Create a Stack Class
+---
+## Create a Stack Class
+
+### Method:
+- Stack is an abstract data structure.
+- Stack follows LIFO/FILO principle.
+- In this challenge, we need to add `.push()`, `.pop()`, `.peek()`, `.isEmpty()` and `.clear()` methods to the class.
+- 
+  - `push()` method pushes value to the stack.
+  - `pop()` method pops the first value from the stack.
+  - `peek()` method returns the first value from the stack.
+  - `isEmpty()` method checks if ths stack is empty.
+  - `.clear()` method removes all the elements from the stack.
+-
+| DS    | Access | Search | Insert | Delete |
+| ----- | ------ | ------ | ------ | ------ |
+| Stack |   n    |    n   |   1    |    1   |
+
+### Solution:
+#### Basic:
+```js
+function Stack() { 
+    var collection = [];
+    this.print = function() {
+        console.log(collection);
+    };
+    this.push = function(val){
+        return collection.push(val);
+    }
+    this.pop = function(){
+        return collection.pop();
+    }
+    this.peek = function(){
+        return collection[collection.length-1];
+    }
+    this.isEmpty = function(){
+        return collection.length === 0;
+    }
+    this.clear = function(){
+        collection.length = 0;
+    }
+}
+```
+#### Advanced - ES6 Class syntax:
+```js
+
+class Stack {
+    constructor() {
+        this.collection = [];
+    }
+    print(){
+        console.log(this.collection);
+    }
+    push(val){
+        retiurn this.collection.push(val);
+    }
+    pop(){
+        return this.collection.pop();
+    }
+    peek(){
+        return this.collection[this.collection.length-1];
+    }
+    isEmpty(){
+        return this.collection.length === 0;
+    }
+    clear(){
+        return this.collection.length = 0;
+    }
+}
+```
+ ### Resources:
+ 
+- [Wikipedia](https://en.wikipedia.org/wiki/Stack_(abstract_data_type))

guide/english/certifications/coding-interview-prep/data-structures/create-a-trie-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Create a Trie Search Tree
+---
+## Create a Trie Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-a-trie-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-an-es6-javascript-map/index.md

@@ -0,0 +1,10 @@
+---
+title: Create an ES6 JavaScript Map
+---
+## Create an ES6 JavaScript Map
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-an-es6-javascript-map/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/create-and-add-to-sets-in-es6/index.md

@@ -0,0 +1,10 @@
+---
+title: Create and Add to Sets in ES6
+---
+## Create and Add to Sets in ES6
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/create-and-add-to-sets-in-es6/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/delete-a-leaf-node-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Delete a Leaf Node in a Binary Search Tree
+---
+## Delete a Leaf Node in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/delete-a-leaf-node-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/delete-a-node-with-one-child-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Delete a Node with One Child in a Binary Search Tree
+---
+## Delete a Node with One Child in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/delete-a-node-with-one-child-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/delete-a-node-with-two-children-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Delete a Node with Two Children in a Binary Search Tree
+---
+## Delete a Node with Two Children in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/delete-a-node-with-two-children-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/depth-first-search/index.md

@@ -0,0 +1,10 @@
+---
+title: Depth-First Search
+---
+## Depth-First Search
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/depth-first-search/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/find-the-minimum-and-maximum-height-of-a-binary-search-tree/index.md

@@ -0,0 +1,55 @@
+---
+title: Find the Minimum and Maximum Height of a Binary Search Tree
+---
+## Find the Minimum and Maximum Height of a Binary Search Tree
+
+Every modern web browser includes a powerful suite of developer tools. These tools do a range of things, from inspecting currently-loaded HTML, CSS and JavaScript to showing which assets the page has requested and how long they took to load. Some of the main features are listed below:
+
+* Access to  a browser console
+* Test Responsive and Device-specific Viewports
+* Edit the DOM
+* Debugging
+* Analyse network activity
+* Understand security issues
+
+and much more...
+
+## How to Open Development Tools
+### Keyboard
+```
+Ctrl + Shift + I
+```
+### Menu bar
+#### Firefox
+```
+Tools ➤ Web Developer ➤ Toggle Tools
+```
+#### Chrome / Chromium
+```
+Tools ➤ Developer Tools
+```
+#### Safari
+```
+Develop ➤ Show Web Inspector.
+```
+If you can't see the Develop menu, go to
+```Safari ➤ Preferences ➤ Advanced```
+and check the ```Show Develop menu``` in menu bar checkbox.
+
+#### Opera
+```
+Developer ➤ Web Inspector
+```
+### Context menu
+```Right-click``` an item on a webpage (Ctrl-click on the Mac), and choose ```Inspect Element``` from the context menu that appears.
+
+This method straight-away highlights the code of the element you right-clicked.
+
+## More Information:
+
+Mozilla Developer Network Web Docs: <a href='https://developer.mozilla.org/en-US/docs/Learn/Common_questions/What_are_browser_developer_tools' target='_blank' rel='nofollow'>What are browser developer tools?</a>
+
+Google Developers: <a href='https://developers.google.com/web/tools/chrome-devtools/
+' target='_blank' rel='nofollow'>Chrome Dev Tools</a>
+
+

guide/english/certifications/coding-interview-prep/data-structures/find-the-minimum-and-maximum-value-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Find the Minimum and Maximum Value in a Binary Search Tree
+---
+## Find the Minimum and Maximum Value in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/find-the-minimum-and-maximum-value-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/implement-heap-sort-with-a-min-heap/index.md

@@ -0,0 +1,10 @@
+---
+title: Implement Heap Sort with a Min Heap
+---
+## Implement Heap Sort with a Min Heap
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/implement-heap-sort-with-a-min-heap/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/incidence-matrix/index.md

@@ -0,0 +1,10 @@
+---
+title: Incidence Matrix
+---
+## Incidence Matrix
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/incidence-matrix/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/index.md

@@ -0,0 +1,13 @@
+---
+title: Data Structures
+---
+## Data Structures
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/mathematics/quadratic-equations/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->
+
+#### More Information:
+<!-- Please add any articles you think might be helpful to read before writing the article -->

guide/english/certifications/coding-interview-prep/data-structures/insert-an-element-into-a-max-heap/index.md

@@ -0,0 +1,10 @@
+---
+title: Insert an Element into a Max Heap
+---
+## Insert an Element into a Max Heap
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/insert-an-element-into-a-max-heap/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/invert-a-binary-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Invert a Binary Tree
+---
+## Invert a Binary Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/invert-a-binary-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/learn-how-a-stack-works/index.md

@@ -0,0 +1,23 @@
+---
+title: Learn how a Stack Works
+---
+## Learn how a Stack Works
+
+### Method:
+- Stacks are an abstract data structures.
+- They follow LIFO (Last In First Out) or FILO (First In Last Out) principle.
+- Stack's insertion and deletion operations are of **O(1)** time complexity.
+- In Javascript, arrays can be treated as a Stack since `.push()` and `.pop()` methods have time complexity of **O(1)**.
+- In this challenge we need to `.pop()` and then `.push()` into the stack.
+
+### Solution:
+```js
+var homeworkStack = ["BIO12","HIS80","MAT122","PSY44"];
+
+homeworkStack.pop();
+homeworkStack.push("CS50");
+```
+### Reference:
+
+- [Wikipedia](https://en.wikipedia.org/wiki/Stack_(abstract_data_type))
+- Video by [Hackerrank](https://www.youtube.com/watch?v=wjI1WNcIntg)

guide/english/certifications/coding-interview-prep/data-structures/perform-a-difference-on-two-sets-of-data/index.md

@@ -0,0 +1,10 @@
+---
+title: Perform a Difference on Two Sets of Data
+---
+## Perform a Difference on Two Sets of Data
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/perform-a-difference-on-two-sets-of-data/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/perform-a-subset-check-on-two-sets-of-data/index.md

@@ -0,0 +1,10 @@
+---
+title: Perform a Subset Check on Two Sets of Data
+---
+## Perform a Subset Check on Two Sets of Data
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/perform-a-subset-check-on-two-sets-of-data/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/perform-a-union-on-two-sets/index.md

@@ -0,0 +1,10 @@
+---
+title: Perform a Union on Two Sets
+---
+## Perform a Union on Two Sets
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/perform-a-union-on-two-sets/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/perform-an-intersection-on-two-sets-of-data/index.md

@@ -0,0 +1,10 @@
+---
+title: Perform an Intersection on Two Sets of Data
+---
+## Perform an Intersection on Two Sets of Data
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/perform-an-intersection-on-two-sets-of-data/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/remove-an-element-from-a-max-heap/index.md

@@ -0,0 +1,10 @@
+---
+title: Remove an Element from a Max Heap
+---
+## Remove an Element from a Max Heap
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/remove-an-element-from-a-max-heap/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/remove-elements-from-a-linked-list-by-index/index.md

@@ -0,0 +1,10 @@
+---
+title: Remove Elements from a Linked List by Index
+---
+## Remove Elements from a Linked List by Index
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/remove-elements-from-a-linked-list-by-index/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/remove-elements-from-a-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Remove Elements from a Linked List
+---
+## Remove Elements from a Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/remove-elements-from-a-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/remove-from-a-set/index.md

@@ -0,0 +1,10 @@
+---
+title: Remove from a Set
+---
+## Remove from a Set
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/remove-from-a-set/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/remove-items-from-a-set-in-es6/index.md

@@ -0,0 +1,10 @@
+---
+title: Remove items from a set in ES6
+---
+## Remove items from a set in ES6
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/remove-items-from-a-set-in-es6/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/reverse-a-doubly-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Reverse a Doubly Linked List
+---
+## Reverse a Doubly Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/reverse-a-doubly-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/search-within-a-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Search within a Linked List
+---
+## Search within a Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/search-within-a-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/size-of-the-set/index.md

@@ -0,0 +1,10 @@
+---
+title: Size of the Set
+---
+## Size of the Set
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/size-of-the-set/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/typed-arrays/index.md

@@ -0,0 +1,21 @@
+---
+title: Typed Arrays
+---
+## Typed Arrays
+
+### Method:
+- In this challenge, first we need to create a buffer of 64 bytes. We can use `ArrayBuffer()` constructor.
+- After creating a buffer we need to create an Int32Array, for that we can use `Int32Array()` constructor.
+
+### Solution:
+```js
+//Create a buffer of 64 bytes
+var buffer = new ArrayBuffer(64);
+
+//Make 32-bit int typed array with the above buffer
+var i32View = new Int32Array(buffer);
+```
+
+### References:
+- [ArrayBuffer](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer)
+- [TypedArray](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays)

guide/english/certifications/coding-interview-prep/data-structures/use-.has-and-.size-on-an-es6-set/index.md

@@ -0,0 +1,10 @@
+---
+title: Use .has and .size on an ES6 Set
+---
+## Use .has and .size on an ES6 Set
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/use-.has-and-.size-on-an-es6-set/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/use-breadth-first-search-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Use Breadth First Search in a Binary Search Tree
+---
+## Use Breadth First Search in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/use-breadth-first-search-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/use-depth-first-search-in-a-binary-search-tree/index.md

@@ -0,0 +1,10 @@
+---
+title: Use Depth First Search in a Binary Search Tree
+---
+## Use Depth First Search in a Binary Search Tree
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/use-depth-first-search-in-a-binary-search-tree/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/use-spread-and-notes-for-es5-set-integration/index.md

@@ -0,0 +1,10 @@
+---
+title: Use Spread and Notes for ES5 Set() Integration
+---
+## Use Spread and Notes for ES5 Set() Integration
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/use-spread-and-notes-for-es5-set-integration/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->

guide/english/certifications/coding-interview-prep/data-structures/work-with-nodes-in-a-linked-list/index.md

@@ -0,0 +1,10 @@
+---
+title: Work with Nodes in a Linked List
+---
+## Work with Nodes in a Linked List
+
+This is a stub. <a href='https://github.com/freecodecamp/guides/tree/master/src/pages/certifications/coding-interview-prep/data-structures/work-with-nodes-in-a-linked-list/index.md' target='_blank' rel='nofollow'>Help our community expand it</a>.
+
+<a href='https://github.com/freecodecamp/guides/blob/master/README.md' target='_blank' rel='nofollow'>This quick style guide will help ensure your pull request gets accepted</a>.
+
+<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds  -->