2016 day12

2 files changed, 16 insertions, 5 deletions

diff --git a/src/2016/day12/README.md b/src/2016/day12/README.md
index f661fc5..b28f890 100644
--- a/src/2016/day12/README.md
+++ b/src/2016/day12/README.md
@@ -26,3 +26,10 @@ dec a
 The above code would set register a to 41, increase its value by 2, decrease its value by 1, and then skip the last dec a (because a is not zero, so the jnz a 2 skips it), leaving register a at 42. When you move past the last instruction, the program halts.
 
 After executing the assembunny code in your puzzle input, what value is left in register a?
+
+--- Part Two ---
+
+As you head down the fire escape to the monorail, you notice it didn't start; register c needs to be initialized to the position of the ignition key.
+
+If you instead initialize register c to be 1, what value is now left in register a?
+
diff --git a/src/2016/day12/aoc.cpp b/src/2016/day12/aoc.cpp
index aac00ff..bd3a395 100644
--- a/src/2016/day12/aoc.cpp
+++ b/src/2016/day12/aoc.cpp
@@ -84,14 +84,14 @@ void jnz(size_t* i, const char* p) {
 
 void non(size_t* i, const char* p) { *i += 1; }
 
-void exec(size_t i, const std::vector<instruction>& todos) {
+size_t exec(size_t i, const std::vector<instruction>& todos) {
   if (i < todos.size()) {
     todo_f fs[5] = {cpy, inc, dec, jnz, non};
     auto d = todos[i];
-    std::cout << d.todo << std::endl;
+    // std::cout << d.todo << std::endl;
     fs[d.which()](&i, d.todo.line + 4);
-    exec(i, todos);
   }
+  return i;
 }
 
 std::pair<int64_t, int64_t> day12(line_view file) {
@@ -100,7 +100,11 @@ std::pair<int64_t, int64_t> day12(line_view file) {
     todos.emplace_back(line_view{lv.line, lv.length - 1});
     return true;
   });
-  // exec(0, todos);
-  return {0, 0};
+  size_t i = 0;
+  while (i < todos.size()) {
+    i = exec(i, todos);
+  }
+
+  return {registers[0], 0};
 }
 } // namespace aoc2016