pub fn y15d04(input: String, leading_zeros: u32) -> Option<u64>Expand description
The solution for the day four challenge.
This function takes the input string and the number of leading zeros to
find as arguments. The logic is otherwise fairly simple, as described
above we batch the work into threads. Each thread works on its chunk of
100,000 numbers combining the input string and each number one after the
other to compute the MD5 hash until it either finds a hash that has the
correct number of leading zeros or it exhausts its numbers. After all
threads have finished we check to see if any results were found and if so
we add them to a vector, sort it, and return the smallest value (this is
important because in theory two threads could find a number that results
in a has with the correct number of leading zeros and we want the smallest
of those numbers). If no answer was found we spawn another batch of the
threads and continue in this way until we either find a match or reach the
maximum integer size (in which case we will return None).
§Example
let input = "a"; // probably read this from the input file...
assert_eq!(y15d04(input.to_string(), 1), Some(27));