Thread: Time complexity and algorithms

I have just completed a problem on project euler, as I progress slowly I have come to realise time complexity is increasingly becoming a major factor. One problem I recently completed took me two hours to run and find solution, probably because I used many loops. From looking at the advice of others, I saw that many had used some brute force algorithm to calculate solution in seconds.

Are there any resources or material relevant to Java from a beginners perspective I can use to learn more about practical brute algorithms or other techniques which will massively reduce the time complexity of my code. If anyone can it would be great if you can share their experience on learning about time complexity and algorithms.

Thank you for taking the time to read.

I have done some Euler problems. Only 20 or so. Your problem is a common one from what I've seen.

My approach was always do it first. If it takes longer than I'd expect then I would do as much research on the the problem as I could and try to refine my logic.

I had a prime number method that would find the first 10,001 primes. It did it in 400m/s. You might say that was fast but a little bit of research and I got it down to 54m/s.

Another way specific to the actual problem your working on. Once you get the answer to the problem, you are granted access to the forum for that question. Users post their solutions and they're a good read. You will learn a lot from them. (Except where people use assembly or mathematica lol)

It certainly comes down to practice though.

Post some questions, they're fun to discuss.

Good luck with Euler.

Thanks guys, I'll keep plodding on.