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#include <filesystem>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <tuple>
#include <vector>
using namespace std;
namespace {
using Grid = vector<vector<long>>;
using Ops = vector<char>;
vector<string>
read_file(const filesystem::path& filename)
{
ifstream file{ filename };
vector<string> lines;
for ( string line; getline(file, line); ) {
lines.emplace_back(line);
}
return lines;
}
vector<char>
read_ops(const string& line)
{
stringstream strm{ line };
vector<char> ops;
for ( char chr{}; strm >> chr; ) {
ops.emplace_back(chr);
}
return ops;
}
vector<long>
read_numbers(const string& line)
{
stringstream strm{ line };
vector<long> numbers;
for ( long number{}; strm >> number; ) {
numbers.emplace_back(number);
}
return numbers;
}
void
part1(vector<string> lines)
{
ranges::reverse(lines);
const auto ops = read_ops(lines[0]);
vector<vector<long>> grid;
for ( size_t i = 1; i < lines.size(); ++i ) {
grid.emplace_back(read_numbers(lines[i]));
}
long sum = 0;
for ( size_t col = 0; col != ops.size(); ++col ) {
long value = ops[col] == '*' ? 1 : 0;
for ( auto& row: grid ) {
if ( ops[col] == '*' ) {
value *= row[col];
}
else {
value += row[col];
}
}
sum += value;
}
cout << "Part 1: " << sum << '\n';
}
vector<string>
rotateLeft90(const vector<string>& matrix)
{
if ( matrix.empty() ) {
return {};
}
auto rows = matrix.size();
auto cols = matrix[0].size();
vector<string> res(cols, string(rows, ' '));
for ( size_t row = 0; row != rows; ++row ) {
for ( size_t col = 0; col != cols; ++col ) {
// Position aus ursprünglicher Matrix auf neue übertragen
res[cols - 1 - col][row] = matrix[row][col];
}
}
return res;
}
void
part2(vector<string> lines)
{
auto ops = read_ops(lines.back());
ranges::reverse(ops);
lines.pop_back(); // ops entfernen
// Matrix drehen
lines = rotateLeft90(lines);
lines.emplace_back("");
vector<vector<long>> grid;
vector<long> curr;
// Matrix neu aufbauen
for ( const auto& line: lines ) {
if ( long number{}; sscanf(line.data(), "%ld", &number) == 1 ) {
curr.emplace_back(number);
}
else {
grid.emplace_back(curr);
curr.clear();
}
}
// ausrechnen
long sum = 0;
for ( size_t row = 0; row != ops.size(); ++row ) {
long value = ops[row] == '*' ? 1 : 0;
for ( const auto number: grid[row] ) {
if ( ops[row] == '*' ) {
value *= number;
}
else {
value += number;
}
}
sum += value;
}
cout << "Part 2: " << sum << '\n';
}
} // namespace
int
main()
{
const auto lines = read_file("data/day06.txt");
part1(lines);
part2(lines);
}
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