From 176d655e3c0a828a200b7e7ae9b184689644cfcb Mon Sep 17 00:00:00 2001
From: Matthew Gretton-Dann <matt@gretton-dann.org.uk>
Date: Sat, 4 Dec 2021 08:04:02 +0000
Subject: [PATCH] Add 2021 Day 4 puzzles

---
 2021/puzzle-04-01.cc | 150 +++++++++++++++++++++++++++++++++++++++++
 2021/puzzle-04-02.cc | 154 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 304 insertions(+)
 create mode 100644 2021/puzzle-04-01.cc
 create mode 100644 2021/puzzle-04-02.cc

diff --git a/2021/puzzle-04-01.cc b/2021/puzzle-04-01.cc
new file mode 100644
index 0000000..1fff0a5
--- /dev/null
+++ b/2021/puzzle-04-01.cc
@@ -0,0 +1,150 @@
+//
+// Created by Matthew Gretton-Dann on 04/12/2021.
+//
+
+#include <array>
+#include <iomanip>
+#include <iostream>
+#include <numeric>
+#include <string>
+#include <utility>
+#include <vector>
+
+using Number = unsigned long;  // NOLINT(google-runtime-int)
+using NumberVector = std::vector<Number>;
+
+auto parse_number_list(std::string const& s) -> NumberVector
+{
+  std::size_t idx{0};
+  NumberVector result;
+  while (idx < s.size()) {
+    std::size_t end{0};
+    result.push_back(std::stoul(s.substr(idx), &end));
+    idx += end;
+    while (idx < s.size() && s[idx] == ',') {
+      ++idx;
+    }
+  }
+  return result;
+}
+
+struct BingoCard
+{
+public:
+  explicit BingoCard(std::array<std::string, 5> const& card)
+  {
+    unsigned row{0};
+    for (auto const& s : card) {
+      std::size_t idx{0};
+      for (unsigned col{0}; col < 5; ++col) {
+        while (s.at(idx) == ' ') {
+          ++idx;
+        }
+        std::size_t end{0};
+        numbers_.at(row + col) = {std::stoul(s.substr(idx), &end), false};
+        idx += end;
+      }
+      assert(idx == s.size());
+
+      row += 5;
+    }
+  }
+
+  void mark(unsigned num)
+  {
+    for (auto it{// NOLINT(llvm-qualified-auto,readability-qualified-auto)
+                 find_num(numbers_.begin(), numbers_.end(), num)};
+         it != numbers_.end(); it = find_num(++it, numbers_.end(), num)) {
+      it->second = true;
+    }
+  }
+
+  [[nodiscard]] auto bingo() const -> bool
+  {
+    for (unsigned row{0}; row < 25; row += 5) {
+      if (std::all_of(numbers_.begin() + row, numbers_.begin() + row + 5,
+                      [](auto const& n) { return n.second; })) {
+        return true;
+      }
+    }
+
+    for (unsigned col{0}; col < 5; ++col) {
+      unsigned marked_count{0};
+      for (unsigned row{col}; row < 25; row += 5) {
+        if (numbers_.at(row).second) {
+          ++marked_count;
+        }
+      }
+      if (marked_count == 5) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  [[nodiscard]] auto score() const -> Number
+  {
+    return std::accumulate(numbers_.begin(), numbers_.end(), Number{0},
+                           [](Number a, auto const& n) { return a + (n.second ? 0 : n.first); });
+  }
+
+  auto print(std::ostream& os) const -> std::ostream&
+  {
+    for (unsigned i = 0; i < 25; ++i) {
+      os << std::setw(3) << numbers_.at(i).first << (numbers_.at(i).second ? "!" : " ")
+         << ((i % 5 == 4) ? '\n' : ' ');
+    }
+    return os;
+  }
+
+private:
+  using NumberPair = std::pair<Number, bool>;
+  using NumberArray = std::array<NumberPair, 25>;
+
+  static auto find_num(NumberArray::iterator begin, NumberArray::iterator end, Number num)
+    -> NumberArray ::iterator
+  {
+    return std::find_if(begin, end, [num](auto const& n) { return n.first == num; });
+  }
+
+  NumberArray numbers_;
+};
+
+auto main() -> int
+{
+  std::string line;
+
+  if (!getline(std::cin, line)) {
+    std::cerr << "Unable to read random numbers.\n";
+    return 1;
+  }
+  NumberVector random_numbers{parse_number_list(line)};
+
+  std::vector<BingoCard> cards;
+  while (std::getline(std::cin, line)) {
+    assert(line.empty());
+    std::array<std::string, 5> lines;
+    for (unsigned row{0}; row < 5; ++row) {
+      std::getline(std::cin, lines.at(row));
+    }
+    cards.emplace_back(lines);
+  }
+
+  for (auto num : random_numbers) {
+    std::cout << num << ", ";
+    for (auto& card : cards) {
+      card.mark(num);
+      if (card.bingo()) {
+        auto score{card.score()};
+        std::cout << "\nBINGO " << score << " * " << num << " = " << score * num << '\n';
+        card.print(std::cout);
+        std::cout << "Num cards: " << cards.size() << '\n';
+        return 0;
+      }
+    }
+  }
+
+  std::cerr << "No bingo!\n";
+  return 1;
+}
\ No newline at end of file
diff --git a/2021/puzzle-04-02.cc b/2021/puzzle-04-02.cc
new file mode 100644
index 0000000..518fc6f
--- /dev/null
+++ b/2021/puzzle-04-02.cc
@@ -0,0 +1,154 @@
+//
+// Created by Matthew Gretton-Dann on 04/12/2021.
+//
+
+#include <array>
+#include <iomanip>
+#include <iostream>
+#include <numeric>
+#include <string>
+#include <utility>
+#include <vector>
+
+using Number = unsigned long;  // NOLINT(google-runtime-int)
+using NumberVector = std::vector<Number>;
+
+auto parse_number_list(std::string const& s) -> NumberVector
+{
+  std::size_t idx{0};
+  NumberVector result;
+  while (idx < s.size()) {
+    std::size_t end{0};
+    result.push_back(std::stoul(s.substr(idx), &end));
+    idx += end;
+    while (idx < s.size() && s[idx] == ',') {
+      ++idx;
+    }
+  }
+  return result;
+}
+
+struct BingoCard
+{
+public:
+  explicit BingoCard(std::array<std::string, 5> const& card)
+  {
+    unsigned row{0};
+    for (auto const& s : card) {
+      std::size_t idx{0};
+      for (unsigned col{0}; col < 5; ++col) {
+        while (s.at(idx) == ' ') {
+          ++idx;
+        }
+        std::size_t end{0};
+        numbers_.at(row + col) = {std::stoul(s.substr(idx), &end), false};
+        idx += end;
+      }
+      assert(idx == s.size());
+
+      row += 5;
+    }
+  }
+
+  void mark(unsigned num)
+  {
+    for (auto it{// NOLINT(llvm-qualified-auto,readability-qualified-auto)
+                 find_num(numbers_.begin(), numbers_.end(), num)};
+         it != numbers_.end(); it = find_num(++it, numbers_.end(), num)) {
+      it->second = true;
+    }
+  }
+
+  [[nodiscard]] auto bingo() const -> bool
+  {
+    for (unsigned row{0}; row < 25; row += 5) {
+      if (std::all_of(numbers_.begin() + row, numbers_.begin() + row + 5,
+                      [](auto const& n) { return n.second; })) {
+        return true;
+      }
+    }
+
+    for (unsigned col{0}; col < 5; ++col) {
+      unsigned marked_count{0};
+      for (unsigned row{col}; row < 25; row += 5) {
+        if (numbers_.at(row).second) {
+          ++marked_count;
+        }
+      }
+      if (marked_count == 5) {
+        return true;
+      }
+    }
+
+    return false;
+  }
+
+  [[nodiscard]] auto score() const -> Number
+  {
+    return std::accumulate(numbers_.begin(), numbers_.end(), Number{0},
+                           [](Number a, auto const& n) { return a + (n.second ? 0 : n.first); });
+  }
+
+  auto print(std::ostream& os) const -> std::ostream&
+  {
+    for (unsigned i = 0; i < 25; ++i) {
+      os << std::setw(3) << numbers_.at(i).first << (numbers_.at(i).second ? "!" : " ")
+         << ((i % 5 == 4) ? '\n' : ' ');
+    }
+    return os;
+  }
+
+private:
+  using NumberPair = std::pair<Number, bool>;
+  using NumberArray = std::array<NumberPair, 25>;
+
+  static auto find_num(NumberArray::iterator begin, NumberArray::iterator end, Number num)
+    -> NumberArray ::iterator
+  {
+    return std::find_if(begin, end, [num](auto const& n) { return n.first == num; });
+  }
+
+  NumberArray numbers_;
+};
+
+auto main() -> int
+{
+  std::string line;
+
+  if (!getline(std::cin, line)) {
+    std::cerr << "Unable to read random numbers.\n";
+    return 1;
+  }
+  NumberVector random_numbers{parse_number_list(line)};
+
+  std::vector<BingoCard> cards;
+  while (std::getline(std::cin, line)) {
+    assert(line.empty());
+    std::array<std::string, 5> lines;
+    for (unsigned row{0}; row < 5; ++row) {
+      std::getline(std::cin, lines.at(row));
+    }
+    cards.emplace_back(lines);
+  }
+
+  auto num{random_numbers.begin()};
+  while (cards.size() > 1 && num != random_numbers.end()) {
+    for (auto card{cards.begin()}; card != cards.end();
+         card = (card->bingo() ? cards.erase(card) : ++card)) {
+      card->mark(*num);
+    }
+    ++num;
+  }
+
+  assert(cards.size() == 1);
+
+  while (!cards[0].bingo() && num != random_numbers.end()) {
+    cards[0].mark(*num++);
+  }
+  --num;
+
+  auto score{cards[0].score()};
+  std::cout << "\nBINGO " << score << " * " << *num << " = " << score * *num << '\n';
+  cards[0].print(std::cout);
+  return 0;
+}
\ No newline at end of file