braindump

Data Structures and Algorithms in JavaScript

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• #egghead #course #javascript #resource

Lessons

Queue Data Structure in JavaScript

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• A queue is a collection of items that obeys the principle of first-in/first-out
• a queue has:
  • add or enqueue method
  • remove or dequeue method
  • peek method: check what’s the next item in the queue
  • length property
  • isEmpty method
• all the operations to our queue should be following the same order
• the length property is a get method, because if we set the length to our closed array length, this will always return the value of the length when we create the queue (which is 0)

Priority Queue JavaScript Data Structure

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• to prioritize a queue, you need to create two queues instead of one.
• the API is the same, but the implementation change a little bit
• for the enqueue method, we need a new parameter to add to the especific queue (high priority or normal)
• for the dequeue we need to first dequeue from the highPriority queue by checking if its empty
• peek does the same check as dequeue
• length is the sum of both queues
• isEmpty should be a check to both queues

Stack Data Structure in JavaScript

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• A stack is a collection of items that obeys the principle of last in, first out (LIFO).
• good to handle nested function calls
• methods:
  • push
  • pop
  • peek
  • length
  • isEmpty
• we need to also add/remove items on the same order, maintaining order is key.

Linked List Data Structure in JavaScript

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• A linked list is a collection of items where each item has a connection to the next item in the list, hence, the word “linked” in the name.
• when adding a new node, we need to use the createNode function

• for every operation to the linked list, we need to update other properties like head, tail, and length manually! (check the video and the community notes. both are ✨)

JavaScript Graph Data Structure

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• A graph is a collection made up of nodes, also known as vertices, that may or may not be connected to other nodes. These connections are called edges.
• Graphs does not have hierarchy
• directed graphs => points to one particular direction
• our graph will have:
  • directed: boolean (determines the direction of our graph)
  • nodes: array
  • edges: array
  • addNode method: creates a node with the passed key
  • getNode method: get a node by finding in the nodes array by key
  • addEdge method:
  • print method
• the print method will show all the nodes and edges of our graph