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#include <algorithm>
#include <cctype>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <numeric>
#include <vector>
using namespace std;
namespace {
vector<vector<long>>
read_file(const filesystem::path& filename)
{
ifstream file{ filename };
vector<vector<long>> lines;
for ( string line; getline(file, line); ) {
vector<long> numbers;
for ( auto chr: line ) {
if ( isdigit(chr) ) {
numbers.emplace_back(chr - '0');
}
}
lines.emplace_back(std::move(numbers));
}
return lines;
}
long
solve(const vector<long>& line, int n)
{
long value = 0;
auto start = line.begin();
while ( n-- > 0 ) {
start = max_element(start, prev(line.end(), n));
value *= 10;
value += *start++;
}
return value;
}
long
solve(const vector<vector<long>>& lines, int n)
{
return accumulate(lines.begin(), lines.end(),
0L,
[&](auto sum, const auto& line) { return sum + solve(line, n); });
}
void
part1(const vector<vector<long>>& lines)
{
cout << "Part 1: " << solve(lines, 2) << '\n';
}
void
part2(const vector<vector<long>>& lines)
{
cout << "Part 2: " << solve(lines, 12) << '\n';
}
} // namespace
int
main()
{
auto lines = read_file("data/day03.txt");
part1(lines);
part2(lines);
}
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