Improved Day 9 Part 2
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8e9b30d451
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93
src/main.rs
93
src/main.rs
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@ -1,5 +1,5 @@
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#![feature(test)]
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#![feature(const_mut_refs)]
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use std::collections::BinaryHeap;
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extern crate test;
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@ -8,35 +8,36 @@ const INPUTS: [&'static str; 2] = [
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include_str!("../inputs/input.txt"),
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];
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fn parse_input(input: &'static str) -> Vec<Vec<u8>> {
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input
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.lines()
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.filter(|&x| !x.is_empty())
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.map(|line| line.bytes().map(|x| x - b'0').collect())
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.collect()
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fn parse_input<const M: usize, const N: usize>(input: &'static str) -> [[u8; N]; M] {
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let mut out = [[0; N]; M];
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for (i, line) in input.lines().filter(|&x| !x.is_empty()).enumerate() {
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for (j, c) in line.bytes().map(|x| x - b'0').enumerate() {
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out[i][j] = c;
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}
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}
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out
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}
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const NEIGHBOURS: [[i32; 2]; 4] = [[-1, 0], [1, 0], [0, -1], [0, 1]];
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fn solution(mut input: Vec<Vec<u8>>) -> u64 {
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let m = input.len() as i32;
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let n = input[0].len() as i32;
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fn solution<const M: usize, const N: usize>(mut input: [[u8; N]; M]) -> u64 {
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let mut heap = BinaryHeap::with_capacity(3);
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for i in 0..m {
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for j in 0..n {
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for i in 0..M {
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for j in 0..N {
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let mut is_minimum = true;
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for &neighbour in NEIGHBOURS.iter() {
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let x = i + neighbour[0];
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let y = j + neighbour[1];
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let x = i as i32 + neighbour[0];
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let y = j as i32 + neighbour[1];
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if x < 0 || y < 0 || x >= m || y >= n {
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if x < 0 || y < 0 || x >= M as i32 || y >= N as i32 {
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continue;
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}
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if input[i as usize][j as usize] >= input[x as usize][y as usize] {
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if input[i][j] >= input[x as usize][y as usize] {
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is_minimum = false;
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break;
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}
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@ -55,45 +56,61 @@ fn solution(mut input: Vec<Vec<u8>>) -> u64 {
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const VISITED: u8 = 1 << 7;
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fn dfs(grid: &mut [Vec<u8>], px: i32, py: i32) -> u64 {
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if grid[px as usize][py as usize] == VISITED {
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#[inline]
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const fn dfs<const M: usize, const N: usize>(grid: &mut [[u8; N]; M], px: usize, py: usize) -> u64 {
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if grid[px][py] == VISITED {
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return 0;
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} else {
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grid[px as usize][py as usize] = VISITED;
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grid[px][py] = VISITED;
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}
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let mut ldepth = 0;
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for neigh in NEIGHBOURS.iter() {
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let x = px as i32 + neigh[0];
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let y = py as i32 + neigh[1];
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if x < 0
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|| y < 0
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|| x >= grid.len() as i32
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|| y >= grid[0].len() as i32
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|| grid[x as usize][y as usize] == 9
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|| grid[x as usize][y as usize] == VISITED
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{
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continue;
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}
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let mut x = px + 1;
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let mut y = py;
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if is_valid_coord::<M, N>(x, y) && grid[x][y] < 9 && grid[x][y] != VISITED {
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ldepth += dfs(grid, x, y);
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}
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x = px;
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y = py + 1;
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if is_valid_coord::<M, N>(x, y) && grid[x][y] < 9 && grid[x][y] != VISITED {
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ldepth += dfs(grid, x, y);
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}
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x = px.wrapping_sub(1);
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y = py;
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if is_valid_coord::<M, N>(x, y) && grid[x][y] < 9 && grid[x][y] != VISITED {
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ldepth += dfs(grid, x, y);
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}
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x = px;
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y = py.wrapping_sub(1);
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if is_valid_coord::<M, N>(x, y) && grid[x][y] < 9 && grid[x][y] != VISITED {
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ldepth += dfs(grid, x, y);
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}
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ldepth + 1
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}
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#[inline]
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const fn is_valid_coord<const M: usize, const N: usize>(x: usize, y: usize) -> bool {
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!(x >= M || y >= N)
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}
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fn main() {
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for input in INPUTS {
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let input = parse_input(input);
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let result = solution(input);
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println!("Result {}", result);
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}
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let input = parse_input::<5, 10>(INPUTS[0]);
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let result = solution::<5, 10>(input);
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println!("Result {}", result);
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let input = parse_input::<100, 100>(INPUTS[1]);
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let result = solution::<100, 100>(input);
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println!("Result {}", result);
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}
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#[bench]
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fn solution_bench(b: &mut test::Bencher) {
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let input = parse_input(INPUTS[1]);
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let input = parse_input::<100, 100>(INPUTS[1]);
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b.iter(|| {
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let result = solution(input.clone());
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test::black_box(result);
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