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2021: day04: do win check when marking number

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This commit is contained in:
Antoine Martin 2021-12-04 15:17:54 +01:00
parent 49e957cff5
commit 45c3426537
1 changed files with 12 additions and 24 deletions
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36
aoc2021/src/day04.rs
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@ -36,7 +36,7 @@ fn part1(input: &str) -> Result<u64> {
'draw_loop: for draw in draws {
for grid in &mut grids {
if grid.mark(draw) && grid.is_winning() {
if grid.mark(draw) {
wgrid = Some(grid.clone());
wdraw = Some(draw);
break 'draw_loop;
@ -77,7 +77,7 @@ fn part2(input: &str) -> Result<u64> {
let mut i = 0;
while i < grids.len() {
let grid = &mut grids[i];
if grid.mark(draw) && grid.is_winning() {
if grid.mark(draw) {
grids.remove(i);
} else {
i += 1;
@ -88,7 +88,7 @@ fn part2(input: &str) -> Result<u64> {
let last_grid = &mut grids[0];
for draw in draws {
if last_grid.mark(draw) && last_grid.is_winning() {
if last_grid.mark(draw) {
return Ok(draw as u64 * last_grid.unmarked_numbers().map(|n| *n as u64).sum::<u64>());
}
}
@ -101,6 +101,8 @@ struct Grid {
number_to_pos: HashMap<u8, (usize, usize)>,
pos_to_number: HashMap<(usize, usize), u8>,
grid: [bool; GRID_SIZE],
rows: [u8; GRID_HEIGHT],
cols: [u8; GRID_WIDTH],
}
impl Grid {
@ -108,32 +110,16 @@ impl Grid {
match self.number_to_pos.get(&draw) {
Some(&(x, y)) => {
*self.access_grid_mut(x, y) = true;
true
self.rows[y] += 1;
self.cols[x] += 1;
self.rows[y] as usize == GRID_WIDTH || self.cols[x] as usize == GRID_HEIGHT
}
None => false,
}
}
fn is_winning(&self) -> bool {
let mut rows = [0u8; GRID_HEIGHT];
let mut cols = [0u8; GRID_WIDTH];
for (y, row) in rows.iter_mut().enumerate() {
for (x, col) in cols.iter_mut().enumerate() {
if self.access_grid(x, y) {
*row += 1;
*col += 1;
if *row as usize == GRID_WIDTH || *col as usize == GRID_HEIGHT {
return true;
}
}
}
}
false
}
fn unmarked_numbers(&self) -> impl Iterator<Item = &u8> {
self.number_to_pos
.iter()
@ -173,6 +159,8 @@ impl std::str::FromStr for Grid {
number_to_pos,
pos_to_number,
grid: [false; GRID_SIZE],
rows: [0; GRID_HEIGHT],
cols: [0; GRID_WIDTH],
})
}
}