Adding Day 2 solution.

input/day2.txt

@@ -0,0 +1 @@
+1,0,0,3,1,1,2,3,1,3,4,3,1,5,0,3,2,10,1,19,1,19,9,23,1,23,6,27,1,9,27,31,1,31,10,35,2,13,35,39,1,39,10,43,1,43,9,47,1,47,13,51,1,51,13,55,2,55,6,59,1,59,5,63,2,10,63,67,1,67,9,71,1,71,13,75,1,6,75,79,1,10,79,83,2,9,83,87,1,87,5,91,2,91,9,95,1,6,95,99,1,99,5,103,2,103,10,107,1,107,6,111,2,9,111,115,2,9,115,119,2,13,119,123,1,123,9,127,1,5,127,131,1,131,2,135,1,135,6,0,99,2,0,14,0

src/day2.cpp

@@ -0,0 +1,75 @@
+#include <iostream>
+#include <fstream>
+#include <string>
+#include <vector>
+#include <cmath>
+
+int run_program(std::vector<int> program, int noun, int verb)
+{
+    int program_counter = 0;
+    bool running = true;
+    program[1] = noun;
+    program[2] = verb;
+    while (running)
+    {
+        auto opcode = program[program_counter++];
+        auto val1 = program[program[program_counter++]];
+        auto val2 = program[program[program_counter++]];
+
+        switch (opcode)
+        {
+        case 1: // addition
+            program[program[program_counter++]] = val1 + val2;
+            break;
+        case 2: // multiplication
+            program[program[program_counter++]] = val1 * val2;
+            break;
+        case 99: // halt
+        default: // unhandled
+            running = false;
+            break;
+        }
+    }
+    return program[0];
+}
+
+int search_program(std::vector<int> program, int expected_value)
+{
+    for (auto noun = 0; noun < 99; noun++)
+    {
+        for (auto verb = 0; verb < 99; verb++)
+        {
+            auto value = run_program(program, noun, verb);
+            if (value == expected_value)
+            {
+                return 100 * noun + verb;
+            }
+        }
+    }
+    return -1;
+}
+
+int main()
+{
+    std::string line;
+    std::ifstream input_file("../input/day2.txt");
+    std::vector<int> program;
+
+    if (input_file.is_open())
+    {
+        while (getline(input_file, line, ','))
+        {
+            program.push_back(std::stoi(line));
+        }
+
+        auto result1 = run_program(program, 12, 2);
+        std::cout << "Part 1 Result: " << result1 << std::endl;
+
+        auto result2 = search_program(program, 19690720);
+        std::cout << "Part 2 Result: " << result2 << std::endl;
+
+        input_file.close();
+    }
+
+    return 0;
+}