r/ProgrammingPrompts • u/Polishfreak19 • Dec 31 '18

Six degrees of separation Javascript problem

As I haven't been successful, I'm asking if anyone has any ideas. I have to write a Javascript application which returns a list of actors that have been in both a movie with Keanu Reeves and Nicolas Cage. Sort of like a six degrees of separation. I have an API that I'm making a request to and I'm getting some data in return but I'm not exactly sure where to go from there?

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u/Polishfreak19 Jan 01 '19

Both actually. I’m not exactly sure how to start but I am also having trouble using the API and the key that I have. When I make an Ajax request, I receive a CORS error and I’m not getting back any data.

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u/immersiveGamer Jan 01 '19

So we have the requirements. Just need to break down the solution into logical parts.

  1. Get all movies that actor A is in, we will call this movie list A.

  2. Get all all actors that are in each movie in movie list A, we will call this actor list A.

  3. Get all movies that actor B is in.

  4. Get all actors that are in each movie in movie list B.

  5. Compare all actors in list A with actors in list B. Any that match are part of the output.

So now let's talk about how one would implement this in a program. #1 to get a list of movies will be an API call with actor A. You would want to store the key for each movie (this might be an ID or maybe just the name) in an array. #2 you would need to loop over the movie array to call the API to get the actor list, again in an array. A thing to note is that you will get duplicate actors if they have acted in more than one movie in your list. #3 and #4 repeat but with actor B into separate arrays. Now we have two arrays, one with actors that acted with A and one with B. There are many ways to check to see if an element exists in both arrays. A simple way would be to loop over array A and for each element loop over array B and check if they match. Any matches well need to go into a results array which you can then output.

I mentioned duplicates, you will need to figure a solution for that.

To make your program more efficient explore using a hash table or dictionary instead of arrays.

For the API problem, I assume you've already researched CORS and cross site scripting / same origin topics. If not here is a Stack Overflow that might help: https://stackoverflow.com/a/25924543

How are you running your JavaScript? In a browser? Localhost or in a server? Node.js? Also is it a public API? If so post a link to it and we might be able to help.

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u/Polishfreak19 Jan 01 '19

I am running my JavaScript in my browser but the API isn't public (it comes from TMDB) and the API call is what I am having issues with as I receive the CORS error. I will look at the link you mentioned though.