Adding And Multiplying In Big O

Add runtimes, if your code does things after each other and multiply them, if you have nested loops.

It is easy to confuse if you have to add or multiply a value to your Big O notation. However, there is a simple rule:

• If your algorithm is in the form of "do this, then when you're done, do that" then add the runtimes.
• If your algorithm is in the form of "do this for each time you do that" then multiply the runtimes

Imagine the difference between two consecutive for loops and two nested for loops.

Links

1. Big O Notation