Stack

• Quick summary: a sequential collection where elements are added to and removed from the same end.
• Important facts:
  • First-in, last-out (FILO) data structure.
  • Equivalent of a real-life pile of papers on desk.
  • In stack terms, to insert is to push, and to remove is to pop.
  • Often implemented on top of a linked list where the head is used for both insertion and removal. Can also be implemented using dynamic arrays.
• Pros:
  • Fast insertions and deletions: O(1).
• Cons:
  • Access and search are O(n).
• Notable uses:
  • Maintaining undo history.
  • Tracking execution of program functions via a call stack.
  • Reversing order of items.
• Time complexity (worst case):
  • Access: O(n)
  • Search: O(n)
  • Insertion (pushing): O(1)
  • Deletion (popping): O(1)
• See also:
  • The Gentle Guide to Stacks
  • Interview Problems: Stacks

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console.log(newStack);

class Stack {

  constructor() {

    this.stack = [];

  }

​

  push(item) {

    return this.stack.push(item);

  }

​

  pop() {

    return this.stack.pop();

  }

​

  peek() {

    return this.stack[this.length - 1];

  }

​

  get length() {

    return this.stack.length;

  }

​

  isEmpty() {

    return this.length === 0;

  }

}

​

const newStack = new Stack();

newStack.push(1);

newStack.push(2);