Add 2016 day 8 puzzles

2016/puzzle-08-01.cc

@@ -0,0 +1,100 @@
+//
+// Created by Matthew Gretton-Dann on 04/12/2021.
+//
+
+#include <array>
+#include <iostream>
+#include <numeric>
+#include <string>
+
+struct Display
+{
+  static constexpr unsigned width{50};
+  static constexpr unsigned height{6};
+
+  [[nodiscard]] auto lit_count() const noexcept -> unsigned
+  {
+    return std::accumulate(grid_.begin(), grid_.end(), unsigned{0},
+                           [](unsigned a, auto i) { return a + (i ? 1 : 0); });
+  }
+
+  auto rect(unsigned w, unsigned h) -> Display
+  {
+    assert(w < width);
+    assert(h < height);
+    Display n{*this};
+    for (unsigned i{0}; i < h; ++i) {
+      for (unsigned j{0}; j < w; ++j) {
+        n.grid_.at(i * width + j) = true;
+      }
+    }
+    return n;
+  }
+
+  auto rotate_column(unsigned col, unsigned amt) -> Display
+  {
+    assert(col < width);
+    amt %= height;
+    Display n(*this);
+    for (unsigned i{0}; i < height; ++i) {
+      auto ni = (i + amt) % height;
+      n.grid_.at(ni * width + col) = grid_.at(i * width + col);
+    }
+    return n;
+  }
+
+  auto rotate_row(unsigned row, unsigned amt) -> Display
+  {
+    assert(row < height);
+    amt %= width;
+    Display n(*this);
+    for (unsigned i{0}; i < width; ++i) {
+      auto ni = (i + amt) % width;
+      n.grid_.at(ni + row * width) = grid_.at(i + row * width);
+    }
+    return n;
+  }
+
+private:
+  std::array<bool, static_cast<std::size_t>(width* height)> grid_{false};
+};
+
+auto begins_with(std::string const& s, std::string const& b) { return s.substr(0, b.size()) == b; }
+
+auto main() -> int
+{
+  const std::string rect_begin{"rect "};
+  const std::string rotate_col_begin{"rotate column x="};
+  const std::string rotate_row_begin{"rotate row y="};
+  Display display{};
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    if (begins_with(line, rect_begin)) {
+      auto idx{rect_begin.size()};
+      std::size_t end{0};
+      auto width{std::stoul(line.substr(idx), &end)};
+      idx += end + 1;
+      auto height{std::stoul(line.substr(idx))};
+      display = display.rect(width, height);
+    }
+    else if (begins_with(line, rotate_col_begin)) {
+      auto idx{rotate_col_begin.size()};
+      std::size_t end{0};
+      auto col{std::stoul(line.substr(idx), &end)};
+      idx += end + 4;
+      auto amt{std::stoul(line.substr(idx))};
+      display = display.rotate_column(col, amt);
+    }
+    else if (begins_with(line, rotate_row_begin)) {
+      auto idx{rotate_row_begin.size()};
+      std::size_t end{0};
+      auto row{std::stoul(line.substr(idx), &end)};
+      idx += end + 4;
+      auto amt{std::stoul(line.substr(idx))};
+      display = display.rotate_row(row, amt);
+    }
+  }
+
+  std::cout << "Number of lit fields: " << display.lit_count() << '\n';
+  return 0;
+}

2016/puzzle-08-02.cc

@@ -0,0 +1,114 @@
+//
+// Created by Matthew Gretton-Dann on 04/12/2021.
+//
+
+#include <array>
+#include <iostream>
+#include <numeric>
+#include <string>
+
+struct Display
+{
+  static constexpr unsigned width{50};
+  static constexpr unsigned height{6};
+
+  [[nodiscard]] auto lit_count() const noexcept -> unsigned
+  {
+    return std::accumulate(grid_.begin(), grid_.end(), unsigned{0},
+                           [](unsigned a, auto i) { return a + (i ? 1 : 0); });
+  }
+
+  auto rect(unsigned w, unsigned h) -> Display
+  {
+    assert(w < width);
+    assert(h < height);
+    Display n{*this};
+    for (unsigned i{0}; i < h; ++i) {
+      for (unsigned j{0}; j < w; ++j) {
+        n.grid_.at(i * width + j) = true;
+      }
+    }
+    return n;
+  }
+
+  auto rotate_column(unsigned col, unsigned amt) -> Display
+  {
+    assert(col < width);
+    amt %= height;
+    Display n(*this);
+    for (unsigned i{0}; i < height; ++i) {
+      auto ni = (i + amt) % height;
+      n.grid_.at(ni * width + col) = grid_.at(i * width + col);
+    }
+    return n;
+  }
+
+  auto rotate_row(unsigned row, unsigned amt) -> Display
+  {
+    assert(row < height);
+    amt %= width;
+    Display n(*this);
+    for (unsigned i{0}; i < width; ++i) {
+      auto ni = (i + amt) % width;
+      n.grid_.at(ni + row * width) = grid_.at(i + row * width);
+    }
+    return n;
+  }
+
+  void print(std::ostream& os) const
+  {
+    for (unsigned i = 0; i < width * height; ++i) {
+      if (i % 5 == 0) {
+        std::cout << " | ";
+      }
+      os << (grid_[i] ? '*' : ' ');
+      if (i % width == (width - 1)) {
+        std::cout << '\n';
+      }
+    }
+  }
+
+private:
+  std::array<bool, static_cast<std::size_t>(width* height)> grid_{false};
+};
+
+auto begins_with(std::string const& s, std::string const& b) { return s.substr(0, b.size()) == b; }
+
+auto main() -> int
+{
+  const std::string rect_begin{"rect "};
+  const std::string rotate_col_begin{"rotate column x="};
+  const std::string rotate_row_begin{"rotate row y="};
+  Display display{};
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    if (begins_with(line, rect_begin)) {
+      auto idx{rect_begin.size()};
+      std::size_t end{0};
+      auto width{std::stoul(line.substr(idx), &end)};
+      idx += end + 1;
+      auto height{std::stoul(line.substr(idx))};
+      display = display.rect(width, height);
+    }
+    else if (begins_with(line, rotate_col_begin)) {
+      auto idx{rotate_col_begin.size()};
+      std::size_t end{0};
+      auto col{std::stoul(line.substr(idx), &end)};
+      idx += end + 4;
+      auto amt{std::stoul(line.substr(idx))};
+      display = display.rotate_column(col, amt);
+    }
+    else if (begins_with(line, rotate_row_begin)) {
+      auto idx{rotate_row_begin.size()};
+      std::size_t end{0};
+      auto row{std::stoul(line.substr(idx), &end)};
+      idx += end + 4;
+      auto amt{std::stoul(line.substr(idx))};
+      display = display.rotate_row(row, amt);
+    }
+  }
+
+  std::cout << "Number of lit fields: " << display.lit_count() << '\n';
+  display.print(std::cout);
+  return 0;
+}