#include <string>
#include <utility> // for std::pair
#include <iostream>
#include <cstdint>
#include <unordered_set>
#include <unordered_map>
//#include <set>
#include <vector>
#include <algorithm>

#include "solutions.hpp"

using namespace std;

pair<string, string> solve1(istream &input) {
    unordered_set<int64_t> seen;
    unordered_map<int64_t, pair<int64_t, int64_t>> targets;
    string part1;
    string part2;
    bool part1_solved = false;
    bool part2_solved = false;
    for(string line; getline(input, line); ) {
        int64_t number = stoi(line);
        if (!part1_solved && seen.contains(2020 - number)) {
            part1 = to_string((2020 - number) * number);
            part1_solved = true;
        }
        if (!part2_solved)  {
            auto search = targets.find(number);
            if (search != targets.end()) {
                part2 = to_string(number * search->second.first * search->second.second);
                part2_solved = true;
            }
            for (int64_t partner : seen) {
                if (number + partner <= 2020) {
                    targets[2020 - number - partner] = pair(number, partner);
                }
            }
        }
        if (part1_solved && part2_solved) {
            return pair(part1, part2);
        }
        seen.insert(number);
    }
    return pair(part1, part2);
}