freeCodeCamp Challenge Guide: Learn how a Stack Works

Learn how a Stack Works


Problem Explanation

  • 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.

Solutions

Solution 1 (Click to Show/Hide)
var homeworkStack = ["BIO12", "HIS80", "MAT122", "PSY44"];

homeworkStack.pop();
homeworkStack.push("CS50");

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