Function aoc::y15d14::y15d14

pub fn y15d14(input: &str, seconds: u32, part: u32) -> u32

The solution for the day fourteen challenge.

As usual we accept the input as a string. Then we take how many seconds of race to process and whether we’re doing part 1 (return the maximum distance) or part 2 (return the maximum number of points). We start by parsing the input and creating our Reindeer objects to track the state as the race progresses. Then for the desired number or race seconds we process each second one-at-a-time. For each second we create a new max-heap (using the venerable std::collections::BinaryHeap to keep track of the current maximum travelled distance. We process each reindeer and add their distance to the heap. We then pop the heap to see what the maximum distance is across all reindeer and then any reindeer who is currently at that winning distance is awarded a point. To return the desired final answer we create a new max-heap and then add each reindeer’s distance for part one or number of obtained points for part two. Popping the heap gives us the answer.

Example

// probably read this from the input file...
let input = concat!(
    "Santa can fly 25 km/s for 10 seconds, but ",
    "then must rest for 10 seconds."
);
assert_eq!(y15d14(input, 100, 1), 1250);
assert_eq!(y15d14(input, 100, 2), 100);