diff --git a/2021/puzzle-22-01.cc b/2021/puzzle-22-01.cc
new file mode 100644
index 0000000..d2ccdce
--- /dev/null
+++ b/2021/puzzle-22-01.cc
@@ -0,0 +1,84 @@
+#include <array>
+#include <iostream>
+#include <regex>
+#include <string>
+
+using Int = long;
+struct Pos
+{
+  constexpr Pos(Int x, Int y, Int z) : x_(x), y_(y), z_(z) {}
+  [[nodiscard]] constexpr auto x() const noexcept -> Int { return x_; }
+  [[nodiscard]] constexpr auto y() const noexcept -> Int { return y_; }
+  [[nodiscard]] constexpr auto z() const noexcept -> Int { return z_; }
+
+private:
+  Int x_{0};
+  Int y_{0};
+  Int z_{0};
+};
+
+constexpr auto operator==(Pos const& lhs, Pos const& rhs) -> bool
+{
+  return lhs.x() == rhs.x() && lhs.y() == rhs.y() && lhs.z() == rhs.z();
+}
+
+constexpr auto operator<(Pos const& lhs, Pos const& rhs) -> bool
+{
+  return lhs.x() < rhs.x() ||
+         (lhs.x() == rhs.x() && (lhs.y() < rhs.y() || (lhs.y() == rhs.y() && lhs.z() < rhs.z())));
+}
+
+struct State
+{
+  void set(Pos const& from, Pos const& to) { set(from, to, true); }
+  void clear(Pos const& from, Pos const& to) { set(from, to, false); }
+  [[nodiscard]] constexpr auto size() const noexcept
+  {
+    return std::count(nodes_.begin(), nodes_.end(), true);
+  }
+
+private:
+  constexpr static Int min_coord{-50};
+  constexpr static Int max_coord{50};
+  constexpr static Int width{max_coord - min_coord + 1};
+
+  void set(Pos const& from, Pos const& to, bool value)
+  {
+    for (auto x{std::max(min_coord, from.x())}; x <= std::min(max_coord, to.x()); ++x) {
+      for (auto y{std::max(min_coord, from.y())}; y <= std::min(max_coord, to.y()); ++y) {
+        for (auto z{std::max(min_coord, from.z())}; z <= std::min(max_coord, to.z()); ++z) {
+          nodes_[(x - min_coord) * width * width + (y - min_coord) * width + (z - min_coord)] =
+            value;
+        }
+      }
+    }
+  }
+
+  std::array<bool, (width * width * width)> nodes_{false};
+};
+
+auto main() -> int
+{
+  std::regex re{R"((on|off) x=(-?\d+)..(-?\d+),y=(-?\d+)..(-?\d+),z=(-?\d+)..(-?\d+))"};
+  std::string line;
+  State state;
+
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::smatch m;
+    if (!std::regex_search(line, m, re)) {
+      std::cout << "Unable to match: " << line << '\n';
+      return 1;
+    }
+
+    Pos from{std::stol(m.str(2)), std::stol(m.str(4)), std::stol(m.str(6))};
+    Pos to{std::stol(m.str(3)), std::stol(m.str(5)), std::stol(m.str(7))};
+    if (m.str(1) == "on") {
+      state.set(from, to);
+    }
+    else {
+      state.clear(from, to);
+    }
+  }
+
+  std::cout << "Number lit: " << state.size() << '\n';
+}
diff --git a/2021/puzzle-22-02.cc b/2021/puzzle-22-02.cc
new file mode 100644
index 0000000..f8752c4
--- /dev/null
+++ b/2021/puzzle-22-02.cc
@@ -0,0 +1,131 @@
+#include <iostream>
+#include <numeric>
+#include <regex>
+#include <string>
+#include <tuple>
+#include <vector>
+
+using Int = std::int64_t;
+struct Pos
+{
+  constexpr Pos(Int x, Int y, Int z) : x_(x), y_(y), z_(z) {}
+  [[nodiscard]] constexpr auto x() const noexcept -> Int { return x_; }
+  [[nodiscard]] constexpr auto y() const noexcept -> Int { return y_; }
+  [[nodiscard]] constexpr auto z() const noexcept -> Int { return z_; }
+
+private:
+  Int x_{0};
+  Int y_{0};
+  Int z_{0};
+};
+
+constexpr auto operator==(Pos const& lhs, Pos const& rhs) -> bool
+{
+  return lhs.x() == rhs.x() && lhs.y() == rhs.y() && lhs.z() == rhs.z();
+}
+
+constexpr auto operator<(Pos const& lhs, Pos const& rhs) -> bool
+{
+  return lhs.x() < rhs.x() ||
+         (lhs.x() == rhs.x() && (lhs.y() < rhs.y() || (lhs.y() == rhs.y() && lhs.z() < rhs.z())));
+}
+
+struct State
+{
+  void add(Pos const& from, Pos const& to, bool set)
+  {
+    x_segments_.push_back(from.x());
+    x_segments_.push_back(to.x() + 1);
+    y_segments_.push_back(from.y());
+    y_segments_.push_back(to.y() + 1);
+    z_segments_.push_back(from.z());
+    z_segments_.push_back(to.z() + 1);
+    instructions_.emplace_back(from, to, set);
+  }
+
+  void calculate()
+  {
+    std::sort(x_segments_.begin(), x_segments_.end());
+    x_segments_.erase(std::unique(x_segments_.begin(), x_segments_.end()), x_segments_.end());
+    std::sort(y_segments_.begin(), y_segments_.end());
+    y_segments_.erase(std::unique(y_segments_.begin(), y_segments_.end()), y_segments_.end());
+    std::sort(z_segments_.begin(), z_segments_.end());
+    z_segments_.erase(std::unique(z_segments_.begin(), z_segments_.end()), z_segments_.end());
+    auto x_size{x_segments_.size()};
+    auto y_size{y_segments_.size()};
+    auto z_size{z_segments_.size()};
+
+    nodes_.resize(x_size * y_size * z_size, false);
+    for (auto const& i : instructions_) {
+      auto xit_begin{std::lower_bound(x_segments_.begin(), x_segments_.end(), std::get<0>(i).x())};
+      auto yit_begin{std::lower_bound(y_segments_.begin(), y_segments_.end(), std::get<0>(i).y())};
+      auto zit_begin{std::lower_bound(z_segments_.begin(), z_segments_.end(), std::get<0>(i).z())};
+      auto xit_end{
+        std::lower_bound(x_segments_.begin(), x_segments_.end(), std::get<1>(i).x() + 1)};
+      auto yit_end{
+        std::lower_bound(y_segments_.begin(), y_segments_.end(), std::get<1>(i).y() + 1)};
+      auto zit_end{
+        std::lower_bound(z_segments_.begin(), z_segments_.end(), std::get<1>(i).z() + 1)};
+      for (auto zit{zit_begin}; zit != zit_end; ++zit) {
+        for (auto yit{yit_begin}; yit != yit_end; ++yit) {
+          for (auto xit{xit_begin}; xit != xit_end; ++xit) {
+            auto x{std::distance(x_segments_.begin(), xit)};
+            auto y{std::distance(y_segments_.begin(), yit)};
+            auto z{std::distance(z_segments_.begin(), zit)};
+            nodes_[z * y_size * x_size + y * x_size + x] = std::get<2>(i);
+          }
+        }
+      }
+    }
+  }
+
+  [[nodiscard]] constexpr auto size() const noexcept -> Int
+  {
+    Int size{0};
+    auto x_size{x_segments_.size()};
+    auto y_size{y_segments_.size()};
+
+    for (auto zit{z_segments_.begin()}; zit + 1 != z_segments_.end(); ++zit) {
+      for (auto yit{y_segments_.begin()}; yit + 1 != y_segments_.end(); ++yit) {
+        for (auto xit{x_segments_.begin()}; xit + 1 != x_segments_.end(); ++xit) {
+          auto x{std::distance(x_segments_.begin(), xit)};
+          auto y{std::distance(y_segments_.begin(), yit)};
+          auto z{std::distance(z_segments_.begin(), zit)};
+          if (nodes_[z * y_size * x_size + y * x_size + x]) {
+            size += (xit[1] - xit[0]) * (yit[1] - yit[0]) * (zit[1] - zit[0]);
+          }
+        }
+      }
+    }
+    return size;
+  }
+
+private:
+  std::vector<std::tuple<Pos, Pos, bool>> instructions_;
+  std::vector<Int> x_segments_;
+  std::vector<Int> y_segments_;
+  std::vector<Int> z_segments_;
+  std::vector<bool> nodes_;
+};
+
+auto main() -> int
+{
+  std::regex re{R"((on|off) x=(-?\d+)..(-?\d+),y=(-?\d+)..(-?\d+),z=(-?\d+)..(-?\d+))"};
+  std::string line;
+  State state;
+
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::smatch m;
+    if (!std::regex_search(line, m, re)) {
+      std::cout << "Unable to match: " << line << '\n';
+      return 1;
+    }
+
+    Pos from(std::stol(m.str(2)), std::stol(m.str(4)), std::stol(m.str(6)));
+    Pos to(std::stol(m.str(3)), std::stol(m.str(5)), std::stol(m.str(7)));
+    state.add(from, to, m.str(1) == "on");
+  }
+
+  state.calculate();
+  std::cout << "Number lit: " << state.size() << '\n';
+}