Improved solution
This commit is contained in:
parent
cc3e2ca1f2
commit
5c0cfb45dd
GPG Key ID:
76BDEC4E165D8AD9
|
|
@ -1,4 +1,7 @@
|
|||
#![feature(test)]
|
||||
use core::fmt;
|
||||
use std::ptr;
|
||||
|
||||
use anyhow::Result;
|
||||
use aoc::Solver;
|
||||
|
||||
|
|
@ -41,31 +44,27 @@ mod tests {
|
|||
Day::benchmark(aoc::Part::TWO, b)
|
||||
}
|
||||
}
|
||||
// -- Helper --
|
||||
fn parse(input: &str) -> (usize, Vec<u32>) {
|
||||
// -- Helpers --
|
||||
fn parse(input: &str) -> (usize, Vec<Vec<u32>>) {
|
||||
let size = input.lines().count();
|
||||
let input = input
|
||||
.lines()
|
||||
.flat_map(|line| line.chars().map(|c| c.to_digit(10).unwrap()).collect::<Vec<_>>())
|
||||
.map(|line| line.chars().filter_map(|c| c.to_digit(10)).collect::<Vec<_>>())
|
||||
.collect::<Vec<_>>();
|
||||
|
||||
(size, input)
|
||||
}
|
||||
|
||||
fn find_highest(size: usize, highest: &mut u32, row: usize, column: usize, tree: u32) -> bool {
|
||||
match (row, column, tree) {
|
||||
(r, _, _) if r == 0 => true,
|
||||
(r, _, _) if r == size-1 => true,
|
||||
(_, c, tree) if c == 0 => {
|
||||
*highest = tree;
|
||||
fn is_visible(size: usize, highest: &mut u32, height: u32, y: usize, x: usize) -> bool {
|
||||
match (y, x, height) {
|
||||
(r, _, _) if r == 0 || r == size-1 => true,
|
||||
(_, c, _) if c == 0 || c == size-1 => {
|
||||
*highest = height;
|
||||
true
|
||||
},
|
||||
(_, c, _) if c == size-1 => {
|
||||
true
|
||||
},
|
||||
(_ ,_, tree) => {
|
||||
if tree > *highest {
|
||||
*highest = tree;
|
||||
(_, _, h) => {
|
||||
if h > *highest {
|
||||
*highest = h;
|
||||
true
|
||||
} else {
|
||||
false
|
||||
|
|
@ -74,72 +73,44 @@ fn find_highest(size: usize, highest: &mut u32, row: usize, column: usize, tree:
|
|||
}
|
||||
}
|
||||
|
||||
// @TODO Figure out if we can do this faster
|
||||
fn transponse<T: Copy>(size: usize, input: &Vec<T>) -> Vec<T> {
|
||||
let mut output = Vec::new();
|
||||
output.reserve(input.len());
|
||||
// Consume the vector and perform the transpose by swapping around elements
|
||||
fn transpose<T: Copy + fmt::Display>(size: usize, mut input: Vec<Vec<T>>) -> Vec<Vec<T>> {
|
||||
for y in 0..size {
|
||||
for x in 0..y {
|
||||
unsafe {
|
||||
let pa: *mut T = &mut input[x][y];
|
||||
let pb: *mut T = &mut input[y][x];
|
||||
|
||||
for c in 0..size {
|
||||
for r in 0..size {
|
||||
output.push(input[r*size + c]);
|
||||
ptr::swap(pa, pb);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
output
|
||||
input
|
||||
}
|
||||
|
||||
fn process_row_reverse((row, line): (usize, &[u32])) -> Vec<bool> {
|
||||
let size = line.len();
|
||||
let mut line = line
|
||||
.iter()
|
||||
.rev()
|
||||
fn process_1d(input: &Vec<Vec<u32>>) -> Vec<Vec<bool>> {
|
||||
input.iter()
|
||||
.enumerate()
|
||||
.scan(0, |highest, (column, tree)| { Some(find_highest(size, highest, row, column, *tree)) })
|
||||
.map(|(y, row)| {
|
||||
let size = row.len();
|
||||
let left = row.iter()
|
||||
.enumerate()
|
||||
.scan(0, |mut highest, (x, &height)| Some(is_visible(size, &mut highest, height, y, x)));
|
||||
|
||||
let mut right = row.iter()
|
||||
.enumerate()
|
||||
.rev()
|
||||
.scan(0, |mut highest, (x, &height)| Some(is_visible(size, &mut highest, height, y, x)))
|
||||
.collect::<Vec<_>>();
|
||||
|
||||
line.reverse();
|
||||
line
|
||||
}
|
||||
right.reverse();
|
||||
|
||||
fn process_row((row, line): (usize, &[u32])) -> Vec<bool> {
|
||||
let size = line.len();
|
||||
line
|
||||
.iter()
|
||||
.enumerate()
|
||||
.scan(0, |highest, (column, tree)| { Some(find_highest(size, highest, row, column, *tree)) })
|
||||
left.zip(right.iter())
|
||||
.map(|(left, &right)| left || right)
|
||||
.collect::<Vec<_>>()
|
||||
}
|
||||
|
||||
fn generate_highest(size: usize, input: &Vec<u32>) -> Vec<bool> {
|
||||
let from_left = input
|
||||
.chunks(size)
|
||||
.enumerate()
|
||||
.flat_map(process_row);
|
||||
|
||||
let from_right = input
|
||||
.chunks(size)
|
||||
.enumerate()
|
||||
.flat_map(process_row_reverse);
|
||||
|
||||
let input = transponse(size, &input);
|
||||
let from_top = input
|
||||
.chunks(size)
|
||||
.enumerate()
|
||||
.flat_map(process_row);
|
||||
|
||||
let from_bottom = input
|
||||
.chunks(size)
|
||||
.enumerate()
|
||||
.flat_map(process_row_reverse);
|
||||
|
||||
let horizontal = from_top.zip(from_bottom).map(|(top, bottom)| top || bottom).collect::<Vec<_>>();
|
||||
let horizontal = transponse(size, &horizontal);
|
||||
|
||||
from_left
|
||||
.zip(from_right)
|
||||
.zip(horizontal.iter())
|
||||
.map(|((left, right), horizontal)| left || right || *horizontal)
|
||||
.collect::<Vec<_>>()
|
||||
}).collect()
|
||||
}
|
||||
|
||||
// -- Solution --
|
||||
|
|
@ -152,90 +123,62 @@ impl aoc::Solver for Day {
|
|||
|
||||
fn part1(input: &str) -> Self::Output {
|
||||
let (size, input) = parse(input);
|
||||
generate_highest(size, &input)
|
||||
.iter()
|
||||
.fold(0, |acc, value| {
|
||||
if *value {
|
||||
acc+1
|
||||
} else {
|
||||
acc
|
||||
}
|
||||
})
|
||||
|
||||
let horizontal = process_1d(&input);
|
||||
let vertical = transpose(size, process_1d(&transpose(size, input)));
|
||||
|
||||
horizontal.iter().flatten().zip(vertical.iter().flatten()).filter(|(&horizontal, &vertical)| horizontal || vertical).count()
|
||||
}
|
||||
|
||||
fn part2(input: &str) -> Self::Output {
|
||||
let (size, input) = parse(input);
|
||||
let map = generate_highest(size, &input);
|
||||
|
||||
map
|
||||
.chunks(size)
|
||||
.enumerate()
|
||||
.flat_map(|(row, line)| line.iter().map(|value| (row, value)).enumerate().collect::<Vec<_>>())
|
||||
.filter_map(|(column, (row, value))| if *value {
|
||||
Some((row, column))
|
||||
} else {
|
||||
None
|
||||
}).map(|(row, column)| {
|
||||
if row == 0 || row == size-1 || column == 0 || column == size-1 {
|
||||
// Value is going to be set to 0
|
||||
return 0;
|
||||
}
|
||||
let height = input[row*size + column];
|
||||
let mut score_highest = 0;
|
||||
for y in 0..size {
|
||||
for x in 0..size {
|
||||
let height = input[y][x];
|
||||
|
||||
let mut distance_left = 0;
|
||||
{
|
||||
for (idx, c) in (0..column).rev().enumerate() {
|
||||
if input[row*size + c] >= height {
|
||||
distance_left = idx + 1;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if distance_left == 0 {
|
||||
distance_left = column;
|
||||
}
|
||||
}
|
||||
|
||||
let mut distance_right = 0;
|
||||
{
|
||||
for (idx, c) in (column+1..size).enumerate() {
|
||||
if input[row*size + c] >= height {
|
||||
distance_right = idx+1;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if distance_right == 0 {
|
||||
distance_right = size-column-1;
|
||||
}
|
||||
}
|
||||
|
||||
let mut distance_up = 0;
|
||||
{
|
||||
for (idx, r) in (0..row).rev().enumerate() {
|
||||
if input[r*size + column] >= height {
|
||||
distance_up = idx + 1;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if distance_up == 0 {
|
||||
distance_up = row;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
let mut distance_down = 0;
|
||||
{
|
||||
for (idx, r) in (row+1..size).enumerate() {
|
||||
if input[r*size + column] >= height {
|
||||
distance_down = idx+1;
|
||||
|
||||
for c in (0..x).rev() {
|
||||
distance_left += 1;
|
||||
if input[y][c] >= height {
|
||||
break;
|
||||
}
|
||||
}
|
||||
if distance_down == 0 {
|
||||
distance_down = size-row-1;
|
||||
|
||||
for c in x+1..size {
|
||||
distance_right += 1;
|
||||
if input[y][c] >= height {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
distance_up * distance_left * distance_down * distance_right
|
||||
}).max().unwrap()
|
||||
for r in (0..y).rev() {
|
||||
distance_up += 1;
|
||||
if input[r][x] >= height {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
for r in y+1..size {
|
||||
distance_down += 1;
|
||||
if input[r][x] >= height {
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
let score = distance_up * distance_left * distance_down * distance_right;
|
||||
|
||||
if score > score_highest {
|
||||
score_highest = score
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
score_highest
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user