diff options
Diffstat (limited to '')
| -rw-r--r-- | 2018/day18.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/2018/day18.c b/2018/day18.c new file mode 100644 index 0000000..686ae70 --- /dev/null +++ b/2018/day18.c @@ -0,0 +1,72 @@ +#include <stdio.h> +#include <stdlib.h> + +typedef unsigned uint; + +struct Map { + char acres[50][50]; +}; + +static uint adjacent(struct Map map, uint y, uint x, char type) { + uint count = 0; + if (y > 0) { + count += (type == map.acres[y - 1][x]); + if (x > 0) count += (type == map.acres[y - 1][x - 1]); + if (x < 49) count += (type == map.acres[y - 1][x + 1]); + } + if (x > 0) count += (type == map.acres[y][x - 1]); + if (x < 49) count += (type == map.acres[y][x + 1]); + if (y < 49) { + count += (type == map.acres[y + 1][x]); + if (x > 0) count += (type == map.acres[y + 1][x - 1]); + if (x < 49) count += (type == map.acres[y + 1][x + 1]); + } + return count; +} + +static struct Map step(struct Map prev) { + struct Map next; + for (uint y = 0; y < 50; ++y) { + for (uint x = 0; x < 50; ++x) { + if (prev.acres[y][x] == '.') { + if (adjacent(prev, y, x, '|') > 2) { + next.acres[y][x] = '|'; + } else { + next.acres[y][x] = '.'; + } + } else if (prev.acres[y][x] == '|') { + if (adjacent(prev, y, x, '#') > 2) { + next.acres[y][x] = '#'; + } else { + next.acres[y][x] = '|'; + } + } else { + if (adjacent(prev, y, x, '#') && adjacent(prev, y, x, '|')) { + next.acres[y][x] = '#'; + } else { + next.acres[y][x] = '.'; + } + } + } + } + return next; +} + +int main(void) { + struct Map map; + for (uint y = 0; y < 50; ++y) { + scanf("%50c\n", map.acres[y]); + } + + for (uint i = 0; i < 10; ++i) { + map = step(map); + } + uint wood = 0, lumber = 0; + for (uint y = 0; y < 50; ++y) { + for (uint x = 0; x < 50; ++x) { + if (map.acres[y][x] == '|') wood++; + if (map.acres[y][x] == '#') lumber++; + } + } + printf("%u\n", wood * lumber); +} |