#include <algorithm>
#include <fstream>
#include <iostream>
#include <sstream>
#include <unordered_map>
#include <vector>

int q1(std::ifstream &in) {
    std::vector<int> l1;
    std::vector<int> l2;
     
 //   for (std::string line; std::getline(in, line);) {
 //       std::string left = line.substr(0, line.find(" "));
 //       std::string right = line.substr(line.rfind(" "));
 //       l1.push_back(std::stoi(left));
 //       l2.push_back(std::stoi(right));
 //   }

    for (std::string line; std::getline(in, line);) {
        int left, right;
        std::stringstream s(line);
        s >> left >> right;
        l1.push_back(left);
        l2.push_back(right);
    }

    std::sort(l1.begin(), l1.end()); 
    std::sort(l2.begin(), l2.end());

    int sum = 0;
    for (int i = 0; i < l1.size(); i++) {
        sum += abs(l1[i]-l2[i]);
    }
    return sum;
}

int q2(std::ifstream &in) {
    std::vector<int> l1;
    std::unordered_map<int, int> l2;
     
    for (std::string line; std::getline(in, line);) {
        std::string left = line.substr(0, line.find(" "));
        std::string right = line.substr(line.rfind(" "));
        l1.push_back(std::stoi(left));
        l2[std::stoi(right)]++;
    }

    std::sort(l1.begin(), l1.end()); 

    int sum = 0;
    for (int i = 0; i < l1.size(); i++) {
        sum += l1[i] * l2[l1[i]];
    }
    return sum;
}

int main() {
    std::ifstream input("i1.txt");
    std::cout << "Part 1: " << q1(input) << std::endl;

    // Could re-read the file, or just seek to the beginning.
    // input = std::ifstream("i1.txt");
    input.clear();
    input.seekg(0);
    std::cout << "Part 2: " << q2(input) << std::endl;
}