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#include <algorithm>
#include <fstream>
#include <iostream>
#include <iterator>
#include <limits>
#include <map>
#include <set>
#include <sstream>
#include <string>
#include <tuple>
#include <vector>
using namespace std;
auto
split(const string& line, char sep = ' ')
{
vector<string> parts;
stringstream input{ line };
for ( string part; getline(input, part, sep); ) {
parts.emplace_back(part);
}
return parts;
}
auto
read_file(string_view filename)
{
fstream input{ filename };
set<string> names;
map<tuple<string, string>, long> table;
for ( string line; getline(input, line); ) {
if ( line.ends_with(".") ) {
line.pop_back();
}
auto parts = split(line);
auto start = parts[0];
auto units = parts[2] == "gain" ? stol(parts[3]) : -stol(parts[3]);
auto end = parts[10]; // NOLINT
table[{ start, end }] = units;
names.insert(start);
}
return table;
}
void
part1(map<tuple<string, string>, long>& table)
{
set<string> unique_names;
for ( const auto& item: table ) {
unique_names.insert(get<0>(item.first));
}
vector<string> names{ begin(unique_names), end(unique_names) };
long happiness_sofar = numeric_limits<long>::min();
do {
long happiness = 0;
for ( size_t idx = 0; idx != names.size(); ++idx ) {
auto next_idx = (idx + 1) % names.size();
happiness += table[{ names[idx], names[next_idx] }];
happiness += table[{ names[next_idx], names[idx] }];
}
happiness_sofar = max(happiness_sofar, happiness);
} while ( next_permutation(begin(names), end(names)) );
cout << happiness_sofar << endl;
}
void
part2(map<tuple<string, string>, long>& table)
{
set<string> unique_names;
for ( const auto& item: table ) {
unique_names.insert(get<0>(item.first));
}
vector<string> names{ begin(unique_names), end(unique_names) };
names.emplace_back("Hartkode");
long happiness_sofar = numeric_limits<long>::min();
do {
long happiness = 0;
for ( size_t idx = 0; idx != names.size(); ++idx ) {
auto next_idx = (idx + 1) % names.size();
happiness += table[{ names[idx], names[next_idx] }];
happiness += table[{ names[next_idx], names[idx] }];
}
happiness_sofar = max(happiness_sofar, happiness);
} while ( next_permutation(begin(names), end(names)) );
cout << happiness_sofar << endl;
}
int
main()
{
auto table = read_file("data/day13.txt");
part1(table);
part2(table);
}
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