banan-os/userspace/aoc2023/day4/main.cpp

93 lines
1.6 KiB
C++
Raw Normal View History

2023-12-04 17:51:27 +02:00
#include <BAN/Vector.h>
#include <BAN/String.h>
#include <BAN/StringView.h>
#include <stdio.h>
#include <string.h>
static int matching_numbers(BAN::StringView line)
{
ASSERT(line.size() == 117);
line = line.substring(0, line.size() - 1);
auto winning_numbers = MUST(line.substring(10, 29).split(' '));
auto your_numbers = MUST(line.substring(42).split(' '));
int matching = 0;
for (auto number : your_numbers)
if (winning_numbers.contains(number))
matching++;
return matching;
}
int puzzle1(FILE* fp)
{
int result = 0;
char buffer[128];
while (fgets(buffer, sizeof(buffer), fp))
{
if (strncmp(buffer, "Card", 4))
continue;
int matching = matching_numbers(buffer);
int points = !!matching;
for (int i = 1; i < matching; i++)
points *= 2;
result += points;
}
return result;
}
int puzzle2(FILE* fp)
{
struct Card
{
BAN::String line;
int count;
};
BAN::Vector<Card> cards;
char buffer[128];
while (fgets(buffer, sizeof(buffer), fp))
if (strncmp(buffer, "Card", 4) == 0)
MUST(cards.emplace_back(BAN::StringView(buffer), 1));
int result = 0;
for (size_t i = 0; i < cards.size(); i++)
{
int matching = matching_numbers(cards[i].line);
for (int j = 0; j < matching; j++)
cards[i + j + 1].count += cards[i].count;
result += cards[i].count;
}
return result;
}
int main(int argc, char** argv)
{
const char* file_path = "/usr/share/aoc2023/day4_input.txt";
if (argc >= 2)
file_path = argv[1];
FILE* fp = fopen(file_path, "r");
if (fp == nullptr)
{
perror("fopen");
return 1;
}
printf("puzzle1: %d\n", puzzle1(fp));
fseek(fp, 0, SEEK_SET);
printf("puzzle2: %d\n", puzzle2(fp));
fclose(fp);
}