From a126076a2687d59f6d204019ccde39cb79a1d2fd Mon Sep 17 00:00:00 2001
From: Matthew Gretton-Dann <matt@gretton-dann.org.uk>
Date: Sat, 2 Dec 2023 09:10:56 +0000
Subject: [PATCH] 2023 Day 2 in a tidy form.

---
 2023/puzzle-02-01.cc |  95 ++++++++++++++++++++++++++++++++++++
 2023/puzzle-02-02.cc | 111 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 206 insertions(+)
 create mode 100644 2023/puzzle-02-01.cc
 create mode 100644 2023/puzzle-02-02.cc

diff --git a/2023/puzzle-02-01.cc b/2023/puzzle-02-01.cc
new file mode 100644
index 0000000..1d83460
--- /dev/null
+++ b/2023/puzzle-02-01.cc
@@ -0,0 +1,95 @@
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+using UInt = std::uint64_t;
+
+struct Balls
+{
+  UInt red_{0};
+  UInt green_{0};
+  UInt blue_{0};
+};
+
+struct Game
+{
+  explicit Game(std::string input)
+  {
+    assert(input.starts_with("Game "));
+    input = input.substr(5);
+    auto pos = std::string::npos;
+    id_ = std::stoul(input, &pos);
+    input = input.substr(pos + 2);
+    Balls balls;
+    while (!input.empty()) {
+      auto value = std::stoul(input, &pos);
+      ++pos;
+      if (input.substr(pos, 3) == "red") {
+        balls.red_ += value;
+        pos += 3;
+      }
+      else if (input.substr(pos, 4) == "blue") {
+        balls.blue_ += value;
+        pos += 4;
+      }
+      else {
+        assert(input.substr(pos, 5) == "green");
+        balls.green_ += value;
+        pos += 5;
+      }
+
+      if (pos == input.size()) {
+        balls_.push_back(balls);
+        return;
+      }
+
+      if (input[pos] == ';') {
+        balls_.push_back(balls);
+        balls = Balls{};
+      }
+      else {
+        assert(input[pos] == ',');
+      }
+
+      pos += 2;
+      input = input.substr(pos);
+    }
+  }
+
+  UInt id_{0};
+  std::vector<Balls> balls_;
+};
+
+auto game_possible(Game const& game, Balls const& max_game) -> bool
+{
+  return std::ranges::all_of(game.balls_.begin(), game.balls_.end(),
+                             [max_game](Balls const& balls) {
+                               return balls.red_ <= max_game.red_ &&
+                                      balls.green_ <= max_game.green_ &&
+                                      balls.blue_ <= max_game.blue_;
+                             });
+}
+
+auto main() -> int try {
+  Balls const max_game{.red_ = 12, .green_ = 13, .blue_ = 14};
+  UInt sum{0};
+
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    Game const game{line};
+    if (game_possible(game, max_game)) {
+      sum += game.id_;
+    }
+  }
+
+  std::cout << "Sum of IDs: " << sum << "\n";
+  return EXIT_SUCCESS;
+}
+catch (...) {
+  std::cerr << "Unexpected exception\n";
+  return EXIT_FAILURE;
+}
diff --git a/2023/puzzle-02-02.cc b/2023/puzzle-02-02.cc
new file mode 100644
index 0000000..83ba114
--- /dev/null
+++ b/2023/puzzle-02-02.cc
@@ -0,0 +1,111 @@
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <numeric>
+#include <string>
+#include <vector>
+
+using UInt = std::uint64_t;
+
+struct Balls
+{
+  UInt red_{0};
+  UInt green_{0};
+  UInt blue_{0};
+};
+
+struct Game
+{
+  explicit Game(std::string input)
+  {
+    assert(input.starts_with("Game "));
+    input = input.substr(5);
+    auto pos = std::string::npos;
+    id_ = std::stoul(input, &pos);
+    input = input.substr(pos + 2);
+    Balls balls;
+    while (!input.empty()) {
+      auto value = std::stoul(input, &pos);
+      ++pos;
+      if (input.substr(pos, 3) == "red") {
+        balls.red_ += value;
+        pos += 3;
+      }
+      else if (input.substr(pos, 4) == "blue") {
+        balls.blue_ += value;
+        pos += 4;
+      }
+      else {
+        assert(input.substr(pos, 5) == "green");
+        balls.green_ += value;
+        pos += 5;
+      }
+
+      if (pos == input.size()) {
+        balls_.push_back(balls);
+        return;
+      }
+
+      if (input[pos] == ';') {
+        balls_.push_back(balls);
+        balls = Balls{};
+      }
+      else {
+        assert(input[pos] == ',');
+      }
+
+      pos += 2;
+      input = input.substr(pos);
+    }
+  }
+
+  [[nodiscard]] auto power() const -> UInt
+  {
+    Balls const balls = std::accumulate(balls_.begin(), balls_.end(),
+                                        Balls{}, [](Balls acc, Balls const& b) {
+                                          if (b.red_ > acc.red_) { acc.red_ = b.red_; }
+                                          if (b.green_ > acc.green_) { acc.green_ = b.green_; }
+                                          if (b.blue_ > acc.blue_) { acc.blue_ = b.blue_; }
+                                          return acc;
+                                        });
+    return balls.red_ * balls.green_ * balls.blue_;
+  }
+
+  UInt id_{0};
+  std::vector<Balls> balls_;
+};
+
+auto game_possible(Game const& game, Balls const& max_game) -> bool
+{
+  return std::ranges::all_of(game.balls_.begin(), game.balls_.end(),
+                             [max_game](Balls const& balls) {
+                               return balls.red_ <= max_game.red_ &&
+                                      balls.green_ <= max_game.green_ &&
+                                      balls.blue_ <= max_game.blue_;
+                             });
+}
+
+auto main() -> int try {
+  Balls const max_game{.red_ = 12, .green_ = 13, .blue_ = 14};
+  UInt sum1{0};
+  UInt power_sum{0};
+
+  std::string line;
+  while (std::getline(std::cin, line)) {
+    Game const game{line};
+    if (game_possible(game, max_game)) {
+      sum1 += game.id_;
+    }
+    power_sum += game.power();
+  }
+
+  std::cout << "Sum of IDs: " << sum1 << "\n";
+  std::cout << "Sum of power: " << power_sum << "\n";
+  return EXIT_SUCCESS;
+}
+catch (...) {
+  std::cerr << "Unexpected exception\n";
+  return EXIT_FAILURE;
+}