Day 2: Red-Nosed Reports
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://blocks.programming.dev/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/22323136
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
I don’t think your solution is O(N^3). Can you explain your reasoning?
3 nested for loops
It’s not as simple as that. You can have 20 nested for loops with complexity of O(1) if all of them only ever finish one iteration.
Or you can have one for loop that iterates 2^N times.
What do you think my complexity is?
I think it could be maybe O(n^2) because the other for loop which tries elements around the first error will only execute a constant of 5 times in the worst case? I’m unsure.
It’s O(n).
If you look at each of the levels of all reports, you will access it a constant number of times: at most twice in each call to
EvaluateLineSafe, and you will callEvaluateLineSafeat most six times for each report.It really depends on what your parameter n is. If the only relevant size is the number of records (let’s say that is n), then this solution takes time in O(n), because it loops over records only once at a time. This ignores the length of records by considering it constant.
If we also consider the maximum length of records (let’s call it m), then your solution, and most others I’ve seen in this thread, has a time complexity in O(n * m^2) for part 2.