58 lines
1.2 KiB
C++
58 lines
1.2 KiB
C++
#include <algorithm>
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#include <fstream>
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#include <iostream>
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#include <numeric>
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#include <sstream>
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#include <unordered_map>
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#include <vector>
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int q1(std::ifstream &in) {
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std::vector<int> l1;
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std::vector<int> l2;
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for (std::string line; std::getline(in, line);) {
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int left, right;
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std::stringstream(line) >> left >> right;
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l1.push_back(left);
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l2.push_back(right);
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}
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std::sort(l1.begin(), l1.end());
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std::sort(l2.begin(), l2.end());
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int sum = 0;
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for (int i = 0; i < l1.size(); i++) {
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sum += abs(l1[i] - l2[i]);
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}
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return sum;
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}
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int q2(std::ifstream &in) {
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std::vector<int> l1;
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std::unordered_map<int, int> l2;
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for (std::string line; std::getline(in, line);) {
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int left, right;
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std::stringstream(line) >> left >> right;
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l1.push_back(left);
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l2[right]++;
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}
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return std::accumulate(l1.begin(), l1.end(), 0, [&l2](int acc, int curr) {
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return acc + curr * l2[curr];
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});
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}
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int main() {
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std::ifstream input("i1.txt");
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std::cout << "Part 1: " << q1(input) << std::endl;
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// Could re-read the file, or just seek to the beginning.
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// input = std::ifstream("i1.txt");
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input.clear();
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input.seekg(0);
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std::cout << "Part 2: " << q2(input) << std::endl;
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}
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