banan-os/userspace/aoc2023/day11/main.cpp

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2023-12-11 14:34:31 +02:00
#include <BAN/Swap.h>
#include <BAN/Vector.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;
using Map = BAN::Vector<BAN::Vector<u8>>;
Map read_map(FILE* fp)
{
Map result;
char buffer[256];
while (fgets(buffer, sizeof(buffer), fp))
{
const size_t len = strlen(buffer);
if (len < 2)
break;
MUST(result.emplace_back(len - 1));
for (size_t i = 0; i < len - 1; i++)
result.back()[i] = buffer[i];
}
return result;
}
i64 distance_with_expansion(const Map& map, u64 x1, u64 y1, u64 x2, u64 y2, u64 expansion_size)
{
ASSERT(map[y1][x1] == '#');
ASSERT(map[y2][x2] == '#');
if (x2 < x1) BAN::swap(x1, x2);
if (y2 < y1) BAN::swap(y1, y2);
u64 expansion_count = 0;
for (u64 y = y1; y < y2; y++)
{
bool is_expanded = true;
for (u64 x = 0; x < map[0].size() && is_expanded; x++)
if (map[y][x] == '#')
is_expanded = false;
expansion_count += is_expanded;
}
for (u64 x = x1; x < x2; x++)
{
bool is_expanded = true;
for (u64 y = 0; y < map.size() && is_expanded; y++)
if (map[y][x] == '#')
is_expanded = false;
expansion_count += is_expanded;
}
return (x2 - x1) + (y2 - y1) + expansion_count * (expansion_size - 1);
}
i64 solution(FILE* fp, u64 expansion)
{
auto map = read_map(fp);
i64 result = 0;
for (size_t i = 0; i < map.size() * map[0].size(); i++)
{
const u64 y1 = i / map[0].size();
const u64 x1 = i % map[0].size();
if (map[y1][x1] != '#')
continue;
for (size_t j = i + 1; j < map.size() * map[0].size(); j++)
{
const u64 y2 = j / map[0].size();
const u64 x2 = j % map[0].size();
if (map[y2][x2] != '#')
continue;
2023-12-11 14:34:31 +02:00
result += distance_with_expansion(map, x1, y1, x2, y2, expansion);
}
}
return result;
}
i64 puzzle1(FILE* fp)
{
return solution(fp, 2);
}
i64 puzzle2(FILE* fp)
{
return solution(fp, 1'000'000);
}
int main(int argc, char** argv)
{
const char* file_path = "/usr/share/aoc2023/day11_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);
}