Add 2021 solutions

src/2021/Day22.cpp

@@ -0,0 +1,138 @@
+#include "common/aoc.h"
+
+namespace y2021::day22
+{
+
+  struct Overlap;
+
+  struct Volume
+  {
+    int sign = 0;
+    Index3D min = Index3D{0, 0};
+    Index3D max = Index3D{0, 0};
+
+    Volume()
+    {
+    }
+
+    Volume(int sign, const Index3D& min, const Index3D& max)
+      : sign{sign},
+        min{min},
+        max{max}
+    {
+    }
+
+    int64_t GetCubes() const
+    {
+      return ((int64_t)max.x - (int64_t)min.x + 1ll) * ((int64_t)max.y - (int64_t)min.y + 1ll) *
+             ((int64_t)max.z - (int64_t)min.z + 1ll);
+    }
+
+    Overlap GetOverlap(const Volume& other) const;
+
+    friend std::ostream& operator<<(std::ostream& stream, const Volume& volume)
+    {
+      return stream << volume.min << " " << volume.max;
+    }
+  };
+
+  struct Overlap
+  {
+    bool overlap = false;
+    Volume volume;
+
+    Overlap(bool overlap, const Volume& volume)
+      : overlap{overlap},
+        volume{volume}
+    {
+    }
+
+    operator bool()
+    {
+      return overlap;
+    }
+  };
+
+  Overlap Volume::GetOverlap(const Volume& other) const
+  {
+    if (min.x > other.max.x || min.y > other.max.y || min.z > other.max.z || max.x < other.min.x ||
+        max.y < other.min.y || max.z < other.min.z)
+      return Overlap{false, Volume{0, Index3D{}, Index3D{}}};
+
+    return Overlap{
+      true,
+      Volume{-other.sign,
+             Index3D{std::max(min.x, other.min.x), std::max(min.y, other.min.y), std::max(min.z, other.min.z)},
+             Index3D{std::min(max.x, other.max.x), std::min(max.y, other.max.y), std::min(max.z, other.max.z)}}};
+  }
+
+  REGISTER_DAY(2021, Day22, std::vector<Volume>, int64_t);
+
+  REGISTER_TEST_EXAMPLE(2021, Day22, ExampleInput, 1, 474140);
+  REGISTER_TEST(2021, Day22, Input, 1, 596598);
+  REGISTER_TEST_EXAMPLE(2021, Day22, ExampleInput, 2, 2758514936282235);
+  REGISTER_TEST(2021, Day22, Input, 2, 1199121349148621);
+
+  READ_INPUT(input)
+  {
+    std::vector<Volume> volumes;
+    std::string str;
+    while (getline(input, str))
+    {
+      Volume volume;
+      std::stringstream ss{str};
+      std::string s;
+      ss >> s >> "x=" >> volume.min.x >> ".." >> volume.max.x >> "," >> "y=" >> volume.min.y >> ".." >> volume.max.y >>
+        "," >> "z=" >> volume.min.z >> ".." >> volume.max.z;
+      volume.sign = s == "on" ? 1 : -1;
+      volumes.emplace_back(volume);
+    }
+    return volumes;
+  }
+
+  OUTPUT1(input)
+  {
+    Array3D<char> values{101, 101, 101};
+    values.Fill('.');
+    for (auto& region : input)
+    {
+      for (int z = std::max(region.min.z, -50); z <= std::min(region.max.z, 50); z++)
+      {
+        for (int y = std::max(region.min.y, -50); y <= std::min(region.max.y, 50); y++)
+        {
+          for (int x = std::max(region.min.x, -50); x <= std::min(region.max.x, 50); x++)
+          {
+            if (values.IsInside(Index3D{x + 50, y + 50, z + 50}))
+            {
+              values.Set(x + 50, y + 50, z + 50, region.sign > 0 ? '#' : '.');
+            }
+          }
+        }
+      }
+    }
+    return values.Count('#');
+  }
+
+  OUTPUT2(input)
+  {
+    std::vector<Volume> volumes;
+    for (auto& volume : input)
+    {
+      size_t size = volumes.size();
+      for (size_t i = 0; i < size; i++)
+      {
+        Overlap overlap = volume.GetOverlap(volumes[i]);
+        if (overlap)
+        {
+          volumes.emplace_back(overlap.volume);
+        }
+      }
+      if (volume.sign > 0)
+      {
+        volumes.emplace_back(volume);
+      }
+    }
+    return Helper::Sum<int64_t>(volumes,
+                                [](int64_t sum, const Volume& vol) { return sum + vol.GetCubes() * vol.sign; });
+  }
+}