Add 2017 day 13 puzzles

2017/puzzle-13-01.cc

@@ -0,0 +1,59 @@
+#include <iostream>
+#include <map>
+#include <regex>
+#include <string>
+
+using UInt = unsigned long;
+
+struct Layer
+{
+  explicit Layer(UInt depth) : depth_(depth) {}
+
+  void advance()
+  {
+    pos_ += dir_;
+    if (pos_ == 0 || pos_ == depth_ - 1) {
+      dir_ = -dir_;
+    }
+  }
+
+  [[nodiscard]] auto pos() const noexcept -> UInt { return pos_; }
+  [[nodiscard]] auto depth() const noexcept -> UInt { return depth_; }
+
+private:
+  UInt pos_{0};
+  UInt depth_;
+  UInt dir_{1};
+};
+
+using LayerMap = std::map<UInt, Layer>;
+
+auto main() -> int
+{
+  static std::regex line_re{"(\\d+): (\\d+)"};
+  std::string line;
+  LayerMap layers;
+
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::smatch m;
+    if (!std::regex_search(line, m, line_re)) {
+      std::cerr << "Unable to match: " << line << '\n';
+      return 1;
+    }
+    layers.insert({std::stoul(m.str(1)), Layer{std::stoul(m.str(2))}});
+  }
+
+  auto severity{0};
+  for (auto& layer : layers) {
+    for (UInt time{0}; time != layer.first; ++time) {
+      layer.second.advance();
+    }
+    if (layer.second.pos() == 0) {
+      severity += layer.first * layer.second.depth();
+    }
+  }
+
+  std::cout << "Severity: " << severity << '\n';
+
+  return 0;
+}

2017/puzzle-13-02.cc

@@ -0,0 +1,63 @@
+#include <iostream>
+#include <map>
+#include <numeric>
+#include <regex>
+#include <string>
+
+using UInt = unsigned long;
+
+struct Layer
+{
+  explicit Layer(UInt depth) : depth_(depth) {}
+
+  [[nodiscard]] auto pos_at(UInt time) const noexcept -> UInt
+  {
+    time %= 2 * (depth_ - 1);
+    if (time < depth_ - 1) {
+      return time;
+    }
+    else {
+      return 2 * (depth_ - 1) - time;
+    }
+  }
+
+  [[nodiscard]] auto depth() const noexcept -> UInt { return depth_; }
+
+private:
+  UInt depth_;
+};
+
+using LayerMap = std::map<UInt, Layer>;
+
+auto main() -> int
+{
+  static std::regex line_re{"(\\d+): (\\d+)"};
+  std::string line;
+  LayerMap layers;
+
+  while (std::getline(std::cin, line) && !line.empty()) {
+    std::smatch m;
+    if (!std::regex_search(line, m, line_re)) {
+      std::cerr << "Unable to match: " << line << '\n';
+      return 1;
+    }
+    layers.insert({std::stoul(m.str(1)), Layer{std::stoul(m.str(2))}});
+  }
+
+  UInt offset{0};
+  UInt cont{true};
+  while (cont) {
+    cont = false;
+    for (auto& layer : layers) {
+      if (layer.second.pos_at(layer.first + offset) == 0) {
+        ++offset;
+        cont = true;
+        break;
+      }
+    }
+  }
+
+  std::cout << "Offset: " << offset << '\n';
+
+  return 0;
+}