[TASK] Added some padding to the grid to save some time on out-of-bounds checks, but it's still pretty slow

src/day10.rs

@@ -7,7 +7,7 @@ pub fn solve() {
     adapters.sort();
 
     let diffs = count_diffs(&adapters);
-    println!("{:?}", diffs);
+    // println!("{:?}", diffs);
     let part1 = (diffs[0] + 1) * (diffs[2] + 1);
 
     println!("Day 10 Part 1: {}", part1);

src/day11.rs

@@ -2,18 +2,17 @@ use super::util;
 use crate::day11::GridState::Floor;
 use crate::day11::GridState::FilledSeat;
 use crate::day11::GridState::EmptySeat;
-use usize_cast::{IntoUsize, FromUsize, IntoIsize, FromIsize};
 
 pub fn solve() {
     let lines = util::read_file("input/day11.txt");
 
-    let seats = Seats::parse(&lines);
-    let visible_chairs = seats.calculate_all_visible_chairs();
+    let seats = Seats::parse(&lines, 1);
 
     let part1 = solve_part1(&seats);
 
     println!("Day 11 Part 1: {}", part1);
 
+    let visible_chairs = seats.calculate_all_visible_chairs();
     let part2 = solve_part2(&seats, &visible_chairs);
 
     println!("Day 11 Part 2: {}", part2);
@@ -26,8 +25,8 @@ fn solve_part1(seats: &Seats) -> usize {
 
     loop {
         let mut changes = false;
-        for y in 0..seats.height {
-            for x in 0..seats.width {
+        for y in 1..seats.height-1 {
+            for x in 1..seats.width-1 {
                 let seat = last_seats.get(&x, &y);
                 if seat != &Floor {
                     let occupied = last_seats.count_occupied_neighbors(&x, &y);
@@ -67,8 +66,8 @@ fn solve_part2(seats: &Seats, visible_chairs: &Vec<Option<Vec<(usize, usize)>>>)
                         changes = true;
                         next_seats.set(&x, &y, FilledSeat);
                     } else if seat == &FilledSeat && occupied >= 5 {
-                        next_seats.set(&x, &y, EmptySeat);
                         changes = true;
+                        next_seats.set(&x, &y, EmptySeat);
                     }
                 }
             }
@@ -95,22 +94,20 @@ impl Seats {
 
     const DIRECTIONS: [(i32, i32); 8] = [(-1, 1), (-1, 0), (-1, -1), (0, -1), (0, 1), (1, 1), (1, 0), (1, -1)];
 
-    fn parse(lines: &Vec<String>) -> Seats {
+    fn parse(lines: &Vec<String>, padding: usize) -> Seats {
 
-        let height = lines.len();
-        let width = lines[0].len();
+        let height = lines.len() + padding * 2;
+        let width = lines[0].len() + padding * 2;
         let mut grid = vec!(GridState::Floor; width * height);
         for y in 0..lines.len() {
             let line = &lines[y];
             let mut line_chars = line.chars();
             for x in 0..lines[0].len() {
-                grid[x + y * width] = GridState::parse(&line_chars.next().unwrap())
+                grid[(x + padding) + (y + padding) * width] = GridState::parse(&line_chars.next().unwrap())
             }
         }
 
-        let mut seats = Seats { grid, width, height };
-        seats.calculate_all_visible_chairs();
-        return seats;
+        return Seats { grid, width, height };
     }
 
     fn calculate_all_visible_chairs(&self) -> Vec<Option<Vec<(usize, usize)>>> {
@@ -141,10 +138,9 @@ impl Seats {
 
     fn raycast(&self, origin_x: &usize, origin_y: &usize, direction: &(i32, i32)) -> Option<(usize, usize)> {
 
-        let mut hit = false;
         let mut x = *origin_x as i32;
         let mut y = *origin_y as i32;
-        while !hit {
+        loop {
 
 
             x = x + direction.0;
@@ -158,7 +154,6 @@ impl Seats {
                 return Option::Some((x as usize, y as usize));
             }
         }
-        return Option::None;
     }
 
     fn is_valid(&self, x: &i32, y: &i32) -> bool {
@@ -175,20 +170,15 @@ impl Seats {
 
     fn count_occupied_neighbors(&self, x: &usize, y: &usize) -> u8 {
 
-        let x_upper = x == &(self.width - &ONE);
-        let x_lower = x == &0;
-        let y_upper = y == &(self.height - &ONE);
-        let y_lower = y == &0;
-
         return
-            if !x_lower && !y_lower && self.is_occupied(&(x - &ONE), &(y - &ONE)) { 1 } else { 0 } +
-            if !x_lower && self.is_occupied(&(x - &ONE), &y) { 1 } else { 0 } +
-            if !x_lower && !y_upper && self.is_occupied(&(x - &ONE), &(y + ONE)) { 1 } else { 0 } +
-            if !y_lower && self.is_occupied(&x, &(y - ONE)) { 1 } else { 0 } +
-            if !y_upper && self.is_occupied(&x, &(y + ONE)) { 1 } else { 0 } +
-            if !x_upper && !y_lower && self.is_occupied(&(x + ONE), &(y - ONE)) { 1 } else { 0 } +
-            if !x_upper && self.is_occupied(&(x + ONE), &y) { 1 } else { 0 } +
-            if !x_upper && !y_upper && self.is_occupied(&(x + ONE), &(y + ONE)) { 1 } else { 0 }
+            if self.is_occupied(&(x - &ONE), &(y - &ONE)) { 1 } else { 0 } +
+            if self.is_occupied(&(x - &ONE), &y) { 1 } else { 0 } +
+            if self.is_occupied(&(x - &ONE), &(y + ONE)) { 1 } else { 0 } +
+            if self.is_occupied(&x, &(y - ONE)) { 1 } else { 0 } +
+            if self.is_occupied(&x, &(y + ONE)) { 1 } else { 0 } +
+            if self.is_occupied(&(x + ONE), &(y - ONE)) { 1 } else { 0 } +
+            if self.is_occupied(&(x + ONE), &y) { 1 } else { 0 } +
+            if self.is_occupied(&(x + ONE), &(y + ONE)) { 1 } else { 0 }
 
     }
 
@@ -205,6 +195,7 @@ impl Seats {
         self.grid[x + y * self.width] = state;
     }
 
+    #[allow(dead_code)]
     fn print(&self) {
 
         for y in 0..self.height {

src/util.rs

@@ -10,12 +10,4 @@ pub fn read_file(filename: &str) -> Vec<String> {
 
     res
 
-}
-
-pub fn add_to_usize(u: usize, i: i32) -> usize {
-    if i.is_negative() {
-        u - i.wrapping_abs() as u32 as usize
-    } else {
-        u + i as usize
-    }
 }