From 07fbabd2ca781f119124ce1e9bec09113c986bd1 Mon Sep 17 00:00:00 2001
From: Shanti Chellaram <shanti@shanti.im>
Date: Sat, 23 Oct 2021 00:56:34 -0400
Subject: [PATCH] Working C++ Day 1

---
 c++/Makefile      |  8 ++++++++
 c++/main.cpp      | 30 ++++++++++++++++++++++++++++++
 c++/problem1.cpp  | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 c++/solutions.hpp |  9 +++++++++
 4 files changed, 93 insertions(+)
 create mode 100644 c++/Makefile
 create mode 100644 c++/main.cpp
 create mode 100644 c++/problem1.cpp
 create mode 100644 c++/solutions.hpp

diff --git a/c++/Makefile b/c++/Makefile
new file mode 100644
index 0000000..d834a23
--- /dev/null
+++ b/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
diff --git a/c++/main.cpp b/c++/main.cpp
new file mode 100644
index 0000000..a1c9d22
--- /dev/null
+++ b/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();
+//}
diff --git a/c++/problem1.cpp b/c++/problem1.cpp
new file mode 100644
index 0000000..8dfd6f5
--- /dev/null
+++ b/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);
+}
diff --git a/c++/solutions.hpp b/c++/solutions.hpp
new file mode 100644
index 0000000..a79a764
--- /dev/null
+++ b/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)