Working C++ Day 1

c++/Makefile

@@ -0,0 +1,8 @@
+aoc-cpp: $(wildcard *.cpp)
+	g++ -std=c++20 -o aoc-cpp $^
+
+all: aoc-cpp
+
+.PHONY: clean
+clean:
+	rm aoc-cpp

c++/main.cpp

@@ -0,0 +1,30 @@
+#include <iostream>
+#include <utility>
+#include <string>
+
+#include "solutions.hpp"
+
+using namespace std; 
+
+int main() {
+    auto x = solve1;
+    auto answer = x(cin);
+    cout << "Solution 1: " << answer.first << endl;
+    cout << "Solution 2: " << answer.second << endl;
+    return 0;
+}
+
+//istream get_input() {
+//    CURL *curl;
+//    CURLcode res;
+//
+//    char url[44] = {0};
+//    sprintf(url, "https://adventofcode.com/2020/day/%d/input");
+//
+//    curl_global_init(CURL_GLOBAL_ALL);
+//    curl = curl_easy_init();
+//    curl_easy_setopt(curl, CURLOPT_URL, "https://adventofcode.com/2020/day/1/input");
+//    curl_easy_setopt(curl, CURLOPT_URL, "https://adventofcode.com/2020/day/1/input");
+//
+//    curl_global_cleanup();
+//}

c++/problem1.cpp

@@ -0,0 +1,46 @@
+#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);
+}

c++/solutions.hpp

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <iostream>
+#include <utility>
+#include <string>
+
+#define DECL_SOLUTION(x) std::pair<std::string, std::string> solve##x(std::istream&);
+
+DECL_SOLUTION(1)