Advent 2022 day2 & day3

advent_of_code_2022/day3/main2.cc

@@ -0,0 +1,44 @@
+#include <fmt/format.h>
+#include <iostream>
+#include <set>
+
+template <typename T>
+struct push_back_set : public std::set<T>
+{
+    void push_back(const T& t)
+    {
+        this->insert(t);
+    }
+};
+
+std::set<char> read_backpack()
+{
+    std::string packing;
+    std::getline(std::cin, packing);
+    return {packing.begin(), packing.end()};
+}
+
+int main()
+{
+    int result = 0;
+
+    while (true)
+    {
+        char badge{};
+        push_back_set<char> b12;
+        
+        auto b1 = read_backpack();
+        auto b2 = read_backpack();
+        auto b3 = read_backpack();
+        
+        std::set_intersection(b1.begin(), b1.end(), b2.begin(), b2.end(), std::back_inserter(b12));
+        std::set_intersection(b12.begin(), b12.end(), b3.begin(), b3.end(), &badge);
+
+        result += std::islower(badge) ? (badge - 'a' + 1) : (badge - 'A' + 27);
+
+        if (std::cin.eof())
+            break;
+    }
+
+    fmt::print("Result: {}\n", result);
+}