Files
advent-of-code/2020/puzzle-06-01.cc

55 lines
1.4 KiB
C++

#include <algorithm>
#include <cassert>
#include <iostream>
#include <string>
// Merge two strings of answers, preserving order and ensuring uniqueness of
// each answer.
std::string merge_answers(std::string const& a, std::string const& b)
{
std::string result;
std::string::size_type pos_a = 0;
std::string::size_type pos_b = 0;
while (pos_a < a.length() && pos_b < b.length()) {
if (a[pos_a] < b[pos_b]) {
result += a[pos_a];
++pos_a;
}
else if (b[pos_b] < a[pos_a]) {
result += b[pos_b];
++pos_b;
}
else {
assert(a[pos_a] == b[pos_b]);
result += a[pos_a];
++pos_a;
++pos_b;
}
}
result += a.substr(pos_a);
result += b.substr(pos_b);
std::cout << "Merged " << a << " and " << b << " to " << result << "\n";
return result;
}
int main(int argc, char** argv)
{
std::string current_answers;
unsigned count = 0;
for (std::string line; std::getline(std::cin, line);) {
if (!line.empty()) {
std::sort(line.begin(), line.end());
current_answers = merge_answers(current_answers, line);
}
else {
std::cout << "Length of " << current_answers << " = " << current_answers.length() << "\n";
count += current_answers.length();
current_answers.clear();
}
}
std::cout << "Length of " << current_answers << " = " << current_answers.length() << "\n";
count += current_answers.length();
std::cout << "Total length = " << count << "\n";
return 0;
}