diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/bin/day5.rs | 35 |
1 files changed, 29 insertions, 6 deletions
diff --git a/src/bin/day5.rs b/src/bin/day5.rs index ed4ae24..afe3b31 100644 --- a/src/bin/day5.rs +++ b/src/bin/day5.rs @@ -1,3 +1,6 @@ +use std::thread; +use std::sync::Arc; + static DAY: u8 = 5; fn main() { @@ -83,18 +86,38 @@ fn lowest_location2(input: &[String]) -> u64 { .map(|x| x.parse().unwrap()) .collect::<Vec<u64>>(); - let range_maps = read_range_map(&input[2..]); + let range_maps = Arc::new(read_range_map(&input[2..])); + + const N_THREADS : u64 = 24; let mut lowest_location = u64::max_value(); for (i, start) in seeds.iter().enumerate().step_by(2) { let range = seeds[i+1]; - for seed in *start..start+range { - let mut next_val = seed; - for category in &range_maps { - next_val = category.map(next_val); + let mut threads = Vec::new(); + let range_per_thread = range / N_THREADS; + for t in 0 .. N_THREADS { + let range_maps = Arc::clone(&range_maps); + let thread_start = start + (t * range_per_thread); + let mut thread_end = thread_start + range_per_thread - 1; + if t == N_THREADS - 1 { + thread_end += range % N_THREADS; } - lowest_location = std::cmp::min(next_val, lowest_location) + + threads.push(thread::spawn(move || { + for seed in thread_start ..= thread_end { + let mut next_val = seed; + for category in range_maps.iter() { + next_val = category.map(next_val); + } + lowest_location = std::cmp::min(next_val, lowest_location) + } + lowest_location + })); + } + + for thread in threads { + lowest_location = std::cmp::min(thread.join().unwrap(), lowest_location); } } |