Initial commit

2015/puzzle-06-02.cc

@@ -0,0 +1,116 @@
+#include <algorithm>
+#include <cassert>
+#include <iostream>
+#include <regex>
+#include <set>
+#include <string>
+
+enum class Action { TurnOn, Toggle, TurnOff };
+using Point = std::pair<unsigned, unsigned>;
+struct Command {
+  Command(std::string const &s) {
+    const char *re =
+        "(turn on|toggle|turn off)\\s(\\d+),(\\d+)\\sthrough\\s(\\d+),(\\d+)";
+    std::smatch m;
+    if (!std::regex_search(s, m, std::regex(re))) {
+      std::cerr << "Unable to interpret:" << s << "\n";
+      assert(false);
+    }
+    if (m.str(1) == std::string("turn on")) {
+      act_ = Action::TurnOn;
+    } else if (m.str(1) == std::string("turn off")) {
+      act_ = Action::TurnOff;
+    } else if (m.str(1) == std::string("toggle")) {
+      act_ = Action::Toggle;
+    } else {
+      assert(false);
+    }
+    bottom_left_.first = std::stoul(m.str(2), nullptr, 10);
+    bottom_left_.second = std::stoul(m.str(3), nullptr, 10);
+    top_right_.first = std::stoul(m.str(4), nullptr, 10);
+    top_right_.second = std::stoul(m.str(5), nullptr, 10);
+  }
+
+  Action act_;
+  Point bottom_left_;
+  Point top_right_;
+};
+
+template <unsigned N> struct Array {
+  Array() noexcept {
+    for (unsigned i = 0; i < N; ++i) {
+      for (unsigned j = 0; j < N; ++j) {
+        lights_[i][j] = 0;
+      }
+    }
+  }
+
+  void apply(Command const &command) noexcept {
+    assert(command.bottom_left_.first < N);
+    assert(command.bottom_left_.second < N);
+    assert(command.top_right_.first < N);
+    assert(command.top_right_.second < N);
+
+    for (unsigned i = command.bottom_left_.first; i <= command.top_right_.first;
+         ++i) {
+      for (unsigned j = command.bottom_left_.second;
+           j <= command.top_right_.second; ++j) {
+        switch (command.act_) {
+        case Action::TurnOn:
+          ++lights_[i][j];
+          break;
+        case Action::Toggle:
+          lights_[i][j] += 2;
+          break;
+        case Action::TurnOff:
+          if (lights_[i][j] > 0) {
+            --lights_[i][j];
+          }
+          break;
+        }
+      }
+    }
+  }
+
+  unsigned brightness() const noexcept {
+    unsigned count = 0;
+    for (unsigned i = 0; i < N; ++i) {
+      for (unsigned j = 0; j < N; ++j) {
+        count += lights_[i][j];
+      }
+    }
+    return count;
+  }
+
+  /// Output a bitmap
+  void bitmap() const {
+    unsigned max = 0;
+    for (unsigned i = 0; i < N; ++i) {
+      for (unsigned j = 0; j < N; ++j) {
+        if (lights_[i][j] > max) {
+          max = lights_[i][j];
+        }
+      }
+    }
+    std::cout << "P2\n" << N << " " << N << "\n" << max << "\n";
+    for (unsigned i = 0; i < N; ++i) {
+      for (unsigned j = 0; j < N; ++j) {
+        std::cout << lights_[i][j] << "\n";
+      }
+    }
+  }
+
+  unsigned lights_[N][N];
+};
+
+int main(int argc, char **argv) {
+  Array<1000> arr;
+  for (std::string line; std::getline(std::cin, line);) {
+    Command cmd(line);
+    arr.apply(cmd);
+  }
+  arr.bitmap();
+  std::cout << arr.brightness() << '\n';
+
+  return 0;
+}