day16: added/optimized

src/day16/1.rs

@@ -1 +1,153 @@
-const INPUTS: [&'static str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+#![feature(test)]
+extern crate test;
+
+const INPUTS: [&[u8]; 2] = [
+    include_bytes!("./sample.txt"),
+    include_bytes!("./input.txt"),
+];
+
+#[derive(Debug, Clone, Eq, PartialEq, Copy)]
+enum Direction {
+    North = 0,
+    South = 1,
+    East = 2,
+    West = 3,
+}
+
+fn process(data: &[u8]) -> usize {
+    let size = data.iter().filter(|&&x| x == b'\n').count();
+    use Direction::*;
+
+    solve(data, size as i32, (0, 0, East))
+}
+
+fn solve(grid: &[u8], size: i32, (sx, sy, dir): (i32, i32, Direction)) -> usize {
+    use Direction::*;
+
+    let mut visited: BitSet<100> = BitSet::new();
+    let mut seen: BitSet<400> = BitSet::new();
+
+    let mut stack = vec![];
+
+    stack.push((sx, sy, dir));
+
+    while let Some((sx, sy, dir)) = stack.pop() {
+        if sx < 0 || sy < 0 || sx >= size || sy >= size {
+            continue;
+        }
+
+        if seen.get(size * size * dir as i32 + size * sx + sy) {
+            continue;
+        } else {
+            seen.set(size * size * dir as i32 + size * sx + sy);
+        }
+
+        visited.set(sx * size + sy);
+        let c = grid[(sx * size + sy + sx) as usize];
+
+        let mut x = sx;
+        let mut y = sy;
+
+        match (c, dir) {
+            (b'\\', East) => stack.push((x + 1, y, South)),
+            (b'\\', North) => stack.push((x, y - 1, West)),
+            (b'\\', West) => stack.push((x - 1, y, North)),
+            (b'\\', South) => stack.push((x, y + 1, East)),
+            (b'/', East) => stack.push((x - 1, y, North)),
+            (b'/', West) => stack.push((x + 1, y, South)),
+            (b'/', South) => stack.push((x, y - 1, West)),
+            (b'/', North) => stack.push((x, y + 1, East)),
+            (b'|', North) => stack.push((x - 1, y, dir)),
+            (b'|', South) => stack.push((x + 1, y, dir)),
+            (b'|', _) => {
+                stack.push((x - 1, y, North));
+                stack.push((x + 1, y, South));
+            }
+            (b'-', East) => stack.push((x, y + 1, dir)),
+            (b'-', West) => stack.push((x, y - 1, dir)),
+            (b'-', _) => {
+                stack.push((x, y + 1, East));
+                stack.push((x, y - 1, West));
+            }
+            (b'.', _) => {
+                let (r, s) = match dir {
+                    North => (-1, 0),
+                    South => (1, 0),
+                    East => (0, 1),
+                    West => (0, -1),
+                };
+
+                loop {
+                    visited.set(x * size + y);
+                    x += r;
+                    y += s;
+                    if x < 0 || y < 0 || x >= size || y >= size {
+                        break;
+                    }
+                    let c = grid[(x * size + y + x) as usize];
+                    if c != b'.' {
+                        break;
+                    }
+                }
+                if !(x < 0 || y < 0 || x >= size || y >= size) {
+                    stack.push((x, y, dir));
+                }
+            }
+
+            _ => unreachable!(),
+        }
+    }
+
+    visited.count()
+}
+
+struct BitSet<const N: usize> {
+    bits: [u128; N],
+}
+
+impl<const N: usize> BitSet<N> {
+    const fn new() -> Self {
+        Self { bits: [0; N] }
+    }
+
+    #[inline]
+    fn set(&mut self, loc: i32) {
+        let idx = loc / 128;
+        let b_idx = loc & 127;
+
+        self.bits[idx as usize] |= 1 << b_idx;
+    }
+
+    #[inline]
+    const fn get(&self, loc: i32) -> bool {
+        let idx = loc / 128;
+        let b_idx = loc & 127;
+
+        (self.bits[idx as usize] & (1 << b_idx)) > 0
+    }
+
+    const fn count(&self) -> usize {
+        let mut count = 0;
+        let mut i = 0;
+        while i < self.bits.len() * 128 {
+            count += self.get(i as i32) as usize;
+            i += 1;
+        }
+
+        count
+    }
+}
+
+fn main() {
+    for input in INPUTS.iter() {
+        println!("answer = {}", process(input));
+    }
+}
+
+#[bench]
+fn part1(b: &mut test::Bencher) {
+    b.iter(|| {
+        let v = process(INPUTS[INPUTS.len() - 1]);
+        test::black_box(v);
+    });
+}

src/day16/2.rs

@@ -1 +1,187 @@
-const INPUTS: [&'static str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+#![feature(test)]
+extern crate test;
+
+const INPUTS: [&[u8]; 2] = [
+    include_bytes!("./sample.txt"),
+    include_bytes!("./input.txt"),
+];
+
+#[derive(Debug, Clone, Eq, PartialEq, Copy)]
+enum Direction {
+    North = 0,
+    South = 1,
+    East = 2,
+    West = 3,
+}
+
+fn process(data: &[u8]) -> usize {
+    let mut maximum = 0;
+
+    let size = data.iter().filter(|&&x| x == b'\n').count();
+
+    use Direction::*;
+    let mut stack = vec![];
+
+    for j in 0..size {
+        let visited = solve(&mut stack, data, size as i32, (0, j as i32, South));
+        maximum = std::cmp::max(maximum, visited);
+
+        let visited = solve(
+            &mut stack,
+            data,
+            size as i32,
+            (size as i32 - 1, j as i32, North),
+        );
+        maximum = std::cmp::max(maximum, visited);
+    }
+
+    for i in 0..size {
+        let visited = solve(&mut stack, data, size as i32, (i as i32, 0, East));
+        maximum = std::cmp::max(maximum, visited);
+
+        let visited = solve(
+            &mut stack,
+            data,
+            size as i32,
+            (i as i32, size as i32 - 1, West),
+        );
+        maximum = std::cmp::max(maximum, visited);
+    }
+
+    maximum
+}
+
+fn solve(
+    stack: &mut Vec<(i32, i32, Direction)>,
+    grid: &[u8],
+    size: i32,
+    (sx, sy, dir): (i32, i32, Direction),
+) -> usize {
+    use Direction::*;
+
+    let mut visited: BitSet<100> = BitSet::new();
+    let mut seen: BitSet<400> = BitSet::new();
+
+    stack.push((sx, sy, dir));
+
+    while let Some((sx, sy, dir)) = stack.pop() {
+        if sx < 0 || sy < 0 || sx >= size || sy >= size {
+            continue;
+        }
+
+        if seen.get(size * size * dir as i32 + size * sx + sy) {
+            continue;
+        } else {
+            seen.set(size * size * dir as i32 + size * sx + sy);
+        }
+
+        visited.set(sx * size + sy);
+        let c = grid[(sx * size + sy + sx) as usize];
+
+        let mut x = sx;
+        let mut y = sy;
+
+        match (c, dir) {
+            (b'\\', East) => stack.push((x + 1, y, South)),
+            (b'\\', North) => stack.push((x, y - 1, West)),
+            (b'\\', West) => stack.push((x - 1, y, North)),
+            (b'\\', South) => stack.push((x, y + 1, East)),
+            (b'/', East) => stack.push((x - 1, y, North)),
+            (b'/', West) => stack.push((x + 1, y, South)),
+            (b'/', South) => stack.push((x, y - 1, West)),
+            (b'/', North) => stack.push((x, y + 1, East)),
+            (b'|', North) => stack.push((x - 1, y, dir)),
+            (b'|', South) => stack.push((x + 1, y, dir)),
+            (b'|', _) => {
+                stack.push((x - 1, y, North));
+                stack.push((x + 1, y, South));
+            }
+            (b'-', East) => stack.push((x, y + 1, dir)),
+            (b'-', West) => stack.push((x, y - 1, dir)),
+            (b'-', _) => {
+                stack.push((x, y + 1, East));
+                stack.push((x, y - 1, West));
+            }
+            (b'.', _) => {
+                let (r, s) = match dir {
+                    North => (-1, 0),
+                    South => (1, 0),
+                    East => (0, 1),
+                    West => (0, -1),
+                };
+
+                loop {
+                    visited.set(x * size + y);
+                    x += r;
+                    y += s;
+                    if x < 0 || y < 0 || x >= size || y >= size {
+                        break;
+                    }
+
+                    let c = grid[(x * size + y + x) as usize];
+                    if c != b'.' {
+                        break;
+                    }
+                }
+                if !(x < 0 || y < 0 || x >= size || y >= size) {
+                    stack.push((x, y, dir));
+                }
+            }
+
+            _ => unreachable!(),
+        }
+    }
+
+    visited.count()
+}
+
+struct BitSet<const N: usize> {
+    bits: [u128; N],
+}
+
+impl<const N: usize> BitSet<N> {
+    const fn new() -> Self {
+        Self { bits: [0; N] }
+    }
+
+    #[inline]
+    fn set(&mut self, loc: i32) {
+        let idx = loc / 128;
+        let b_idx = loc & 127;
+
+        self.bits[idx as usize] |= 1 << b_idx;
+    }
+
+    #[inline]
+    const fn get(&self, loc: i32) -> bool {
+        let idx = loc / 128;
+        let b_idx = loc & 127;
+
+        (self.bits[idx as usize] & (1 << b_idx)) > 0
+    }
+
+    const fn count(&self) -> usize {
+        let mut count = 0;
+        let mut i = 0;
+        while i < self.bits.len() * 128 {
+            count += self.get(i as i32) as usize;
+            i += 1;
+        }
+
+        count
+    }
+}
+
+fn main() {
+    for input in INPUTS.iter() {
+        println!("answer = {}", process(input));
+    }
+}
+
+#[bench]
+fn part2(b: &mut test::Bencher) {
+    b.iter(|| {
+        let v = process(INPUTS[INPUTS.len() - 1]);
+        test::black_box(v);
+    });
+}

src/day16/input.txt

@@ -0,0 +1,110 @@
+\..-.-..../.....|......\......................\............\.................|..............|........./.|.....
+...-\...|............|......../.|........-../................|.-..............-....\.|..|.....................
+.|..........\................\\|................../..........................\\../|...-...-.|..........\......
+..................|\....|.....-.......................-........\.............................|/...............
+.......-...........-......................./........../.......-............................\.....-.....-.../..
+./.\...../....../..........\..............|............|....|........................\..../.../...|\..........
+..................................../...............................................\..................-.\....
+......../.........................|...............................|...............\|\........\....|....\......
+.--.........................../.../.......-.\........../.\.........|...............\..|.....\-.....\....||\...
+......\............|......../..\................-..............\-..-...|\.../-............/.........|...\.....
+.........|.........-.........|............/............-..............\../.......-.|\\..|......./.............
+..........................\........|.....\...../..-......-............../.-|.............\.\...../.......\....
+.....\.................-........../........-....|.....-......|.....................................-......-\..
+......|\......................................./...../........|...|....../..................-....-.-..../.....
+.../......\...|./|..........\.......-./..-../.................\.....\......../........./..|......-...|.../....
+--|................\.................|........../......\|......|.........................\....................
+......../...........|./............../.....-.....-......../.................................-.....-...........
+........................-.../..../..\|..............................|\..|.|\................/........-...\...|
+\.........-....../...|.\............./......\.......\..../....\|./-|.........|......-.......\............|....
+....|..........-.....|..../..........-/...-.............\..\...................\................|......|......
+............-..|...........-..../...-........../.../...-....-....../\..............|........\..............--.
+.....\.../......|..-..............|..-........................|......|.......|.........\............/...\...-.
+|....................-.........../.....-........\.../..........|..............................................
+..-.............|..../............|........................|..../.........................\..........-..-.../.
+........-.|......\.........../................/..|..\................./.|....-................../...-......./.
+\|..-.......\..............\.|/......-|.........../........../.-...............\....\....\..|..|..............
+..........|.........\............\\.../../|...........-................|....................|....|-\/\...\....
+.-........\............-.......\............-.............\.\......./...........././.|.\-...-.\./..........-/.
+../.................-........//--...........|........./..../....|.....................................|....\..
+.............|....|........|........./.....\..../..-..................../........|.....././...................
+......................-....\..........--.....\..\........../...........................--/....................
+.|.../.......-.......\.......|.............................-.............\..-.\../.......|............|......\
+...../.......-......|.............../.../...........................................|......-..........-.......
+.............\............................................../......................\......../.................
+|....................-...-\..................\................/.../...........................................
+..|....-............/....................../......../...../......./.......\.-................/................
+.........../..-/...-...\..............-..../...............-|.........-............/........|.|.-...|...\.....
+....../..-../.........-|...../...........................\..............-..................--...-.............
+-.................-......../.....|....................\....................-../....................|./.....-..
+......./...\......../.|.|.........-.................................../....|..................................
+...|........\|\.........\...\...-......-...............................\.......//.|.....-.............../.....
+........................../.|-...|....\..........\...................-..-............../............../.......
+........../..-.......-....\.......\.............\.|................................|......../..............-..
+.......-................................-..................|../...\....................................-......
+...................................................................................../...\...................-
+..\.-...................................|..............-.....|.........\..................../.........-....\..
+...................../\......-...........--.../............|...........|.....\....//.....-........./...-|.....
+......||.........|.-.........................|.........|.||..-....-......|.................\.-../.............
+...|.........|.......\....\................................../.................../....\................\......
+..................../|...............||.-/........|../..................................../.\......\...-......
+......./........./..-............................-.................\...|...............-................-.....
+.............................--...-....\......................................|..........\...-......./........
+.......\...-.............../......\/.........................|........./..........|...........................
+.........|.................................|.........../.|................................../...........-....|
+...|...-...|...........................-....-.....................|../|........|...................../.....|..
+.......-.....-..................\.-........|...-..../........\.......................\......|..........-......
+|......................\..........-...............|........................../...........|....................
+................|....|..................-......-/.......-....|..\.../\.|.....-..../...................../.|..\
+............/........................../....-........-...............-...|...............|..\............./...
+................./................\.............../...........\........\....../............\.....|........./..
+..\......./.-.....................-............-./......|..........-.............\..../.......................
+/..../....-........\................................\....|.............../\-.............................-|...
+................\..................\.--.|......//....|..|....|....../..................|.|...|....-|-.........
+...................\............\....-............\...........................................-./.............
+.........................\../............|..\.........../................/..../.............-.................
+..-..\.........../............|..................................../............/.....-..............|.....|..
+..|/......\||.......\............/....|........|.-........./.............|.....................|./............
+..........-............../...........................................|.............|..-..../.|................
+..|.../..|......................./..-.-..............\../....................-..|............-...../.-........
+.-....../..............\..................\................./....-...\....\...-.....\.....-.-..............\./
+............./..../.\........-..\................................\....../.|.....|.......|.........|....\......
+.-.....\.-......-.|.-.........../..|...........\....................................\........|.//./.......-...
+......-.......-/.........................-...../........|............./..................../............-.....
+.............\....|......-../...........\...................../...............................................
+../.......................................-...../.|..\......|...-......../....|./..........\.........|........
+....../.............\...................................\........\....-.........../..../..\..................|
+.../...-.....-................/.........|....................|..............-.........\.......................
+...................../..............-.......|......................./...|.....|../.|............../..........\
+.././....../........-........|.../.........../|..........|....../......-.....\.............................\..
+............|........|................/....\..............\............/.....\../..............|....../.......
+|................\..../...........................|.......\......\.....\........../....../....................
+........./...-...\......./....................-...................................-............\........-..../
+............./............../.....................\.-..../.................\.........|.|............../.-...\\
+.........|......-\......\.................../..|.........|......\....\..-..\-.................................
+...............|../.......................-.../......\......|||................|..............................
+.|...-............./...........-.......................|...............................|..............\.......
+.|.............|.........................................-........|-.\.................-/.|...................
+.|.......-||.........../..\....\.....................-....-....-.......-......-.........-|........|...........
+.........\........-...|........../............/.................../......./........................-..........
+............\.........................../..\.......-............/.......................|.........\...........
+..\..\............/..................../..............-....../|.../...................|............./..../....
+..\.\....\.../............/.../.........................../.-.......-.....\......|........|...../.........|.\|
+.....-...........\..............-......-....-...../........-......|...../..\..|/........-............./.../...
+.....\.......-........\...-.............................................|....||.........|...-......\..........
+............|......................../.....-........././..............................................\.....\.
+.\.........\......../........................-.............|........\../.../...-......\................|.....-
+....|................|/.....................\........|........................./|.....\...-../.|......../-....
+/..............-......-..............|..|.|.....................-\.|../...\..............................|.../
+....\/.........|\....-..............\......-.....................\............\........................\......
+......-...................\...............-/../........-.../....................\./..........-................
+..........................\.......|......\.|\....../......\......../........-/............................/.|.
+.......-....\...................................../..............|../.......|......./..........|--.......-....
+...-...|.............................|........-.....-.|...........|.....|..............\..............-.......
+-.\...........\......|.\.............................\...........|.........\.............../\.................
+...../....................\../|...........................\.........|..................|........\.|..-../.....
+.-....-../.................................\....../......|....../..............-...........-../...\.../.......
+.\........-............................../..-...................|/..........|............................/....
+../|..........|.........../...-....../.....|.-./...\....-....\|.\.....|........./.-.....\.....|./........|....
+............\.....\...................-.\-.-\|...............................\...............\.....-..........
+...|................-......................\....|..\.-..........|............../.....-...................../..

src/day16/sample.txt

@@ -0,0 +1,10 @@
+.|...\....
+|.-.\.....
+.....|-...
+........|.
+..........
+.........\
+..../.\\..
+.-.-/..|..
+.|....-|.\
+..//.|....