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May 24, 2017

Stacks: Data Structures & Algorithms in JavaScript P.2

I’m learning about data structures and algorithms in JavaScript. I’m using various online resources and going to be sharing my notes as a series of blog posts. The topics are below:
  • Data Structures: List ADT | Stacks | Queues | Linked Lists | Trees, Tries & Graphs | Heaps | Hash Tables
  • Algorithms: Breadth-First Search | Depth-First Search | Binary Search | Merge Sort | Quick Sort
  • Concepts: Memory (Stack vs. Heap) | Recursion | Big O Time & Space

2. Stacks

  • A stack is a list of elements that are only accessible from the top of the list.
  • As such, a stack is referred to as a Last-in, First-out (LIFO) data structure.
  • It is efficient and fast because we can add or remove data only from the top of the list.
  • Any element that is not at the top of the stack can not be accessed directly.
  • The push method adds an element to the top of the stack, while pop removes an element from the top of a stack.
  • The peek method returns the value of the element at the top without removing it as pop does.
  • The top property tracks the top position of the stack while the dataStore is a an array used to store data internally.
  • Eg. usage: ‘undo’ operation of a text editor.
  • Here is an implementation of a Stack class:
  • An example using the Stack class: