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‫In this course, we're going to spend a lot of time on big.

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‫Oh, it is a huge topic when it comes to data structures and algorithms.

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‫So what is Bigo?

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‫O is a way of comparing two sets of code and let's say code one and code to accomplish exactly the same

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‫thing.

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‫How would you compare one against the other?

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‫Code one might be more readable.

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‫That might be better.

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‫CO two might be more concise.

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‫The code might take up fewer lines, and if that's what you're measuring, then you would say that code

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‫two is better.

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‫Big O is a way of comparing code one and code two mathematically about how efficient they run.

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‫In a coding interview, you will absolutely be asked questions about Big O.

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‫So let's look at what Big O is.

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‫Let's say we have a stopwatch.

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‫And we run code one, we start the stopwatch and it runs for 15 seconds.

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‫And we reset the stopwatch and we run code two.

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‫And code two runs a lot longer than 15 seconds.

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‫It runs for a full minute.

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‫Based on this, you would say that code one is better than code two.

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‫You can measure it.

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‫This is called time complexity.

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‫The thing about time complexity that is interesting is that it is not measured in time.

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‫Because if you took the same code and ran it on a computer that runs twice as fast, it would complete

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‫twice as fast.

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‫It doesn't make the code any better.

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‫It just means the computer is better.

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‫So it is measured in the number of operations that it takes to complete something.

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‫And we'll look at examples of that as we go along here.

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‫In addition to time complexity, we measure space complexity.

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‫So let's say that code one.

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‫While it runs very fast comparatively, let's say it takes up a lot of memory when it runs.

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‫And maybe code too, even though that takes much longer to finish.

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‫Maybe it takes up less memory.

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‫If preserving memory space is your most important priority and you don't mind having some extra time

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‫complexity.

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‫Maybe CO two is better.

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‫So when you get into an interview, there's a good chance that you'll be asked questions about time,

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‫complexity, and then they'll say, Hey, well, what if space complexity is our main priority?

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‫How would you approach it?

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‫Then you have to understand both concepts and be able to address that in the job interview.

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‫But for the most part in this class, we will be dealing.

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‫With time complexity.

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‫And that is our quick intro.

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‫Big O.