11

day11.cpp

@@ -15,8 +15,8 @@ auto Compute(Machine machine, ValueType start)
   
   Coord here {0,0};
   std::map<Coord, ValueType> paint {{here,start}};
-  ValueType dx = 1;
-  ValueType dy = 0;
+  ValueType dx {0};
+  ValueType dy {-1};
 
   for (;;) {
     auto effect = machine.Step();
@@ -26,9 +26,8 @@ auto Compute(Machine machine, ValueType start)
     }
 
     std::get<Input>(effect).pos = paint[here];
-    auto color = std::get<Output>(machine.Step()).val;
+    paint[here] = std::get<Output>(machine.Step()).val;
     auto dir = std::get<Output>(machine.Step()).val;
-    paint[here] = color;
 
     std::swap(dx, dy);
     if (dir) {  
@@ -41,16 +40,27 @@ auto Compute(Machine machine, ValueType start)
   }
 }
 
-auto Draw(std::map<Coord, ValueType> image) {
-  ValueType minX = 1000, maxX = -1000, minY = 1000, maxY = -1000;
+auto Draw(std::ostream & out, std::map<Coord, ValueType> image) {
+  ValueType minX = 0, maxX = 0, minY = 0, maxY = 0;
+  for (auto&& [k, _] : image) {
+    auto [x,y] = k;
+    minX = std::min(minX, x);
+    maxX = std::max(maxX, x);
+    minY = std::min(minY, y);
+    maxY = std::max(maxY, y);
+  }
+  for (ValueType y = minY; y <= maxY; y++) {
+    for (ValueType x = minX; x <= maxX; x++) {
+      out << (image[{x,y}] ? "▓" : "░");
+    }
+    out << "\n";
+  }
 }
 
 } // namespace
 
 auto main() -> int {
   auto machine = Machine{ParseStream(std::cin)};
-
-  std::cout << "Part 1: " << Compute(machine, 0).size() << std::endl;
-  
-  Draw(Compute(std::move(machine), 1));
+  std::cout << "Part 1: " << Compute(machine, 0).size() << "\nPart 2\n";
+  Draw(std::cout, Compute(std::move(machine), 1));
 }

lib/intcode.cpp

@@ -21,7 +21,7 @@ auto Ref(Machine & m, ValueType instruction, std::size_t k, ValueType p)
   case 1:
     return v;
   case 2:
-    return m.At(m.Rel(v));
+    return m.Rel(v);
   default:
     throw BadInstruction{"invalid addressing mode"};
   }