Day 1/30 back to DSA challenge

Source: Dev.to

DSA

• Reviewed notes on DSA.
• Solved the Two Sum problem using a hashmap and the complement technique.
  • Instead of storing each element and checking sums, store the complement (target - current number).
  • When a number matches a stored complement, return the indices of the two numbers.

Promises

• Discussed asynchronous programming in JavaScript.
• Synchronous execution runs line‑by‑line; a long‑running operation (e.g., an API request) blocks subsequent lines.
• Asynchronous execution allows other code to run while waiting for the operation to complete.
• A callback is a function passed as an argument to be executed later.
• Nested callbacks lead to “callback hell.”
• Promises provide a cleaner way to handle asynchronous operations and avoid callback hell.

So this is what I learned today. I will be much more productive in my next challenge. I Promise! (haha)