Files
advent-of-code/2020/puzzle-06-02.cc

68 lines
1.2 KiB
C++

#include <algorithm>
#include <cassert>
#include <iostream>
#include <map>
#include <string>
using OccuranceMap = std::map<char, unsigned>;
struct GroupAnswers
{
void add_answers(std::string const& a)
{
// Increase group size
++group_size_;
// Add answers
for (auto c : a) {
auto it = map_.find(c);
if (it == map_.end()) {
map_.insert({c, 1});
}
else {
++(it->second);
}
}
}
// Count the number of answered questions answered by everyone.
unsigned all_answer_count() const noexcept
{
unsigned count = 0;
for (auto kv : map_) {
if (kv.second == group_size_) {
++count;
}
}
return count;
}
void clear()
{
map_.clear();
group_size_ = 0;
}
OccuranceMap map_;
unsigned group_size_ = 0;
};
int main(int argc, char** argv)
{
GroupAnswers answers;
unsigned count = 0;
for (std::string line; std::getline(std::cin, line);) {
if (!line.empty()) {
answers.add_answers(line);
}
else {
count += answers.all_answer_count();
answers.clear();
}
}
count += answers.all_answer_count();
std::cout << "Total length = " << count << "\n";
return 0;
}