2023 Day 14

2023/puzzle-14-01.cc

@@ -0,0 +1,72 @@
+#include <algorithm>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+using UInt = std::uint64_t;
+
+struct Grid
+{
+  void push_back(std::string const& row) { rows_.push_back(row); }
+
+  void roll_north()
+  {
+    for (auto row{rows_.begin() + 1}; row != rows_.end(); ++row) {
+      for (std::size_t col{0}; col < row->size(); ++col) {
+        if (row->at(col) == 'O') {
+          auto new_row = row - 1;
+          while (new_row != rows_.begin() && new_row->at(col) == '.') { --new_row; }
+          if (new_row->at(col) != '.') { ++new_row; }
+          if (new_row != row) {
+            new_row->at(col) = 'O';
+            row->at(col) = '.';
+          }
+        }
+      }
+    }
+  }
+
+  [[nodiscard]] auto load() const -> UInt
+  {
+    UInt load{0};
+    for (std::size_t row{0}; row != rows_.size(); ++row) {
+      auto count = std::count_if(rows_[row].begin(), rows_[row].end(),
+                                 [](char c) { return c == 'O'; });
+      load += count * (rows_.size() - row);
+    }
+    return load;
+  }
+
+  friend auto operator<<(std::ostream& os, Grid const& grid) -> std::ostream&;
+
+private:
+  std::vector<std::string> rows_;
+};
+
+auto operator<<(std::ostream& os, Grid const& grid) -> std::ostream&
+{
+  for (auto const& row : grid.rows_) { os << row << '\n'; }
+  return os;
+}
+
+auto main() -> int try {
+  std::string line;
+
+  Grid grid;
+  while (std::getline(std::cin, line)) {
+    grid.push_back(line);
+  }
+
+  std::cout << "Read in grid:\n" << grid;
+  grid.roll_north();
+  std::cout << "Rolled grid:\n" << grid;
+  std::cout << "Load: " << grid.load() << '\n';
+
+  return EXIT_SUCCESS;
+}
+catch (...) {
+  std::cerr << "Uncaught exception.\n";
+  return EXIT_FAILURE;
+}