156 lines
2.6 KiB
C++
156 lines
2.6 KiB
C++
#include <BAN/Vector.h>
|
|
#include <BAN/HashSet.h>
|
|
|
|
#include <ctype.h>
|
|
#include <inttypes.h>
|
|
#include <stdio.h>
|
|
|
|
using i8 = int8_t;
|
|
using i16 = int16_t;
|
|
using i32 = int32_t;
|
|
using i64 = int64_t;
|
|
|
|
using u8 = uint8_t;
|
|
using u16 = uint16_t;
|
|
using u32 = uint32_t;
|
|
using u64 = uint64_t;
|
|
|
|
enum class Tile { Free, Rock };
|
|
|
|
struct Position
|
|
{
|
|
i64 x;
|
|
i64 y;
|
|
|
|
Position operator+(const Position& other) const
|
|
{
|
|
return {
|
|
.x = x + other.x,
|
|
.y = y + other.y
|
|
};
|
|
}
|
|
|
|
bool operator==(const Position& other) const
|
|
{
|
|
return x == other.x && y == other.y;
|
|
}
|
|
};
|
|
|
|
namespace BAN
|
|
{
|
|
template<>
|
|
struct hash<Position>
|
|
{
|
|
hash_t operator()(const Position& position) const
|
|
{
|
|
return hash<u64>()(((u64)position.x << 32) | (u64)position.y);
|
|
}
|
|
};
|
|
}
|
|
|
|
struct Garden
|
|
{
|
|
Position start;
|
|
BAN::Vector<BAN::Vector<Tile>> tiles;
|
|
};
|
|
|
|
Garden parse_garden(FILE* fp)
|
|
{
|
|
Garden garden;
|
|
|
|
i64 row = 0;
|
|
|
|
char buffer[256];
|
|
while (fgets(buffer, sizeof(buffer), fp))
|
|
{
|
|
BAN::StringView line(buffer);
|
|
ASSERT(line.back() == '\n');
|
|
line = line.substring(0, line.size() - 1);
|
|
if (line.empty())
|
|
break;
|
|
|
|
MUST(garden.tiles.emplace_back(line.size(), Tile::Free));
|
|
for (size_t i = 0; i < line.size(); i++)
|
|
{
|
|
if (line[i] == '#')
|
|
garden.tiles.back()[i] = Tile::Rock;
|
|
if (line[i] == 'S')
|
|
garden.start = { .x = (i64)i, .y = row };
|
|
}
|
|
|
|
row++;
|
|
}
|
|
|
|
return garden;
|
|
}
|
|
|
|
i64 puzzle1(FILE* fp)
|
|
{
|
|
auto garden = parse_garden(fp);
|
|
|
|
BAN::HashSet<Position> visited, reachable, pending;
|
|
MUST(pending.insert(garden.start));
|
|
|
|
for (i32 i = 0; i <= 64; i++)
|
|
{
|
|
auto temp = BAN::move(pending);
|
|
pending = BAN::HashSet<Position>();
|
|
|
|
while (!temp.empty())
|
|
{
|
|
auto position = *temp.begin();
|
|
temp.remove(position);
|
|
|
|
MUST(visited.insert(position));
|
|
if (i % 2 == 0)
|
|
MUST(reachable.insert(position));
|
|
|
|
Position offsets[4] { { -1, 0 }, { 1, 0 }, { 0, -1 }, { 0, 1 } };
|
|
for (i32 j = 0; j < 4; j++)
|
|
{
|
|
auto next = position + offsets[j];
|
|
if (next.y < 0 || next.y >= (i64)garden.tiles.size())
|
|
continue;
|
|
if (next.x < 0 || next.x >= (i64)garden.tiles[0].size())
|
|
continue;
|
|
if (garden.tiles[next.y][next.x] == Tile::Rock)
|
|
continue;
|
|
if (visited.contains(next))
|
|
continue;
|
|
MUST(pending.insert(next));
|
|
}
|
|
}
|
|
}
|
|
|
|
return reachable.size();
|
|
}
|
|
|
|
i64 puzzle2(FILE* fp)
|
|
{
|
|
(void)fp;
|
|
return -1;
|
|
}
|
|
|
|
int main(int argc, char** argv)
|
|
{
|
|
const char* file_path = "/usr/share/aoc2023/day21_input.txt";
|
|
|
|
if (argc >= 2)
|
|
file_path = argv[1];
|
|
|
|
FILE* fp = fopen(file_path, "r");
|
|
if (fp == nullptr)
|
|
{
|
|
perror("fopen");
|
|
return 1;
|
|
}
|
|
|
|
printf("puzzle1: %" PRId64 "\n", puzzle1(fp));
|
|
|
|
fseek(fp, 0, SEEK_SET);
|
|
|
|
printf("puzzle2: %" PRId64 "\n", puzzle2(fp));
|
|
|
|
fclose(fp);
|
|
}
|