00:00:00,500 --> 00:00:02,450 BRIAN YU: Let's take a look at similarities. In the similarities problem, your task is going to be to take two files and to figure out how similar they are to each other. But what does similar actually mean? Two files could be similar because they have a lot of lines in common, for example. Or two files could be similar because they have a lot of sentences in common. Or two files could be similar because they have a lot of substrings in common. And your task in this problem is going to be to explore all three of those different methods. So here's what you'll have to do. First, you'll implement a function called lines, which will compare two files based on the number of lines they have in common. Then, you'll implement a function called sentences, which will compare files based on the number of sentences that they have in common. And then, you'll implement a function called substrings, which will compare files based on the number of substrings of length n they have in common for any length n. And then finally, we'll take these functions to the web, writing an HTML file called index.html, which will display a web form where the user can select two files and how they want to compare them-- either by lines, or sentences, or substrings-- and then submit that form, at which point your web page will display-- side-by-side-- those two files with any similarities between them highlighted. Let's get started.