Some of my project euler solutions that I wrote in Java. To speed things up, I frequently make use of every core on my machine. Not every solution I have here correctly solves the problems, just the ones described below.
The sudoku solver uses simulated annealing with a preliminary check that attempts to solve (and fill in as many cells as it can) by deduction.
This step should help the randomised step.
Uses simple brute force with O(n2) to check.
Generates cubes and stores it's already seen permutations in a HashMap. Once any sorted cube has 5 permutations,
stop.
Generates squares until it matches the given regex.
Brute forces.
Uses a sliding window to gradually increase the length of the sum until the maximum is reached. Generates all primes below one-million and sorts them.