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#include <filesystem>
#include <fstream>
#include <iostream>
#include <vector>
using namespace std;
namespace {
vector<int>
read_file(const filesystem::path& filename)
{
ifstream file{ filename };
vector<int> data;
for ( int number{}; file >> number; ) {
data.emplace_back(number);
}
return data;
}
void
part1(const vector<int>& data)
{
size_t idx = 0;
int sum = 0;
function<void()> func = [&] {
auto count_child = data.at(idx++);
auto count_meta = data.at(idx++);
while ( count_child-- > 0 ) {
func();
}
while ( count_meta-- > 0 ) {
sum += data.at(idx++);
}
};
func();
cout << "Part 1: " << sum << '\n';
}
void
part2(const vector<int>& data)
{
size_t idx = 0;
function<int()> func = [&] {
const auto count_child = data.at(idx++);
const auto count_meta = data.at(idx++);
vector<int> child_values;
for ( int i = 0; i != count_child; ++i ) {
child_values.emplace_back(func());
}
int value = 0;
for ( int i = 0; i != count_meta; ++i ) {
auto meta = data.at(idx++);
if ( count_child == 0 ) {
value += meta;
}
else {
meta--;
if ( meta >= 0 && meta < count_child ) {
value += child_values[static_cast<size_t>(meta)];
}
}
}
return value;
};
cout << "Part 2: " << func() << '\n';
}
} // namespace
int
main()
{
auto data = read_file("data/day08.txt");
part1(data);
part2(data);
}
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