Solutions for 2018 day 11

2018/puzzle-11-01.cc

@@ -0,0 +1,66 @@
+//
+// Created by Matthew Gretton-Dann on 01/12/2022.
+//
+
+#include <array>
+#include <cstdlib>
+#include <iomanip>
+#include <iostream>
+#include <regex>
+#include <utility>
+
+constexpr std::size_t grid_size{300};
+using Int = std::int64_t;
+using Grid = std::array<std::array<Int, grid_size>, grid_size>;
+using SmallGrid = std::array<std::array<Int, grid_size - 2>, grid_size - 2>;
+
+auto main() -> int
+{
+  std::string line;
+  if (!std::getline(std::cin, line)) {
+    std::cerr << "Unable to read line.\n";
+    return EXIT_FAILURE;
+  }
+
+  Int const serial{std::stoll(line)};
+  Grid grid;
+  for (Int y{0}; y < grid_size; ++y) {
+    for (Int x{0}; x < grid_size; ++x) {
+      Int const rack_id{x + 1 + 10};
+      Int power{(rack_id * (y + 1) + serial) * rack_id};
+      power /= 100;
+      power %= 10;
+      power -= 5;
+      grid.at(y).at(x) = power;
+    }
+  }
+
+  SmallGrid small_grid;
+  for (Int y{0}; y < small_grid.size(); ++y) {
+    for (Int x{0}; x < small_grid.size(); ++x) {
+      small_grid[y][x] = 0;
+      for (Int dy{0}; dy < 3; ++dy) {
+        for (Int dx{0}; dx < 3; ++dx) {
+          small_grid[y][x] += grid[y + dy][x + dx];
+        }
+      }
+    }
+  }
+
+  Int max_power{std::numeric_limits<Int>::min()};
+  Int max_x{0};
+  Int max_y{0};
+  for (Int y{0}; y < small_grid.size(); ++y) {
+    for (Int x{0}; x < small_grid.size(); ++x) {
+      if (max_power < small_grid[y][x]) {
+        max_power = small_grid[y][x];
+        max_x = x + 1;
+        max_y = y + 1;
+      }
+    }
+  }
+  std::cout << "Maximum power: " << max_power << "\n";
+  std::cout << "Coordinates: " << max_x << "," << max_y << "\n";
+
+  return EXIT_SUCCESS;
+}

2018/puzzle-11-02.cc

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+//
+// Created by Matthew Gretton-Dann on 01/12/2022.
+//
+
+#include <array>
+#include <cstdlib>
+#include <iomanip>
+#include <iostream>
+#include <regex>
+#include <utility>
+
+constexpr std::size_t grid_size{300};
+using Int = std::int64_t;
+using Grid = std::array<std::array<Int, grid_size>, grid_size>;
+using SmallGrid = std::array<std::array<Int, grid_size - 2>, grid_size - 2>;
+
+auto main() -> int
+{
+  std::string line;
+  if (!std::getline(std::cin, line)) {
+    std::cerr << "Unable to read line.\n";
+    return EXIT_FAILURE;
+  }
+
+  Int const serial{std::stoll(line)};
+  Grid grid;
+  for (Int y{0}; y < grid_size; ++y) {
+    for (Int x{0}; x < grid_size; ++x) {
+      Int const rack_id{x + 1 + 10};
+      Int power{(rack_id * (y + 1) + serial) * rack_id};
+      power /= 100;
+      power %= 10;
+      power -= 5;
+      grid.at(y).at(x) = power;
+    }
+  }
+
+  Int max_power{std::numeric_limits<Int>::min()};
+  Int max_x{0};
+  Int max_y{0};
+  Int max_g{0};
+
+  Grid small_grid{grid};
+
+  for (Int g{0}; g < grid_size; ++g) {
+    Int sgs(grid_size - g);
+    for (Int y{0}; y < sgs; ++y) {
+      for (Int x{0}; x < sgs; ++x) {
+        for (Int dx{0}; dx <= g; ++dx) {
+          small_grid[y][x] += grid[y + g][x + dx];
+        }
+        for (Int dy{0}; dy < g; ++dy) {
+          small_grid[y][x] += grid[y + dy][x + g];
+        }
+
+        if (max_power < small_grid[y][x]) {
+          max_power = small_grid[y][x];
+          max_x = x + 1;
+          max_y = y + 1;
+          max_g = g + 1;
+        }
+      }
+    }
+  }
+  std::cout << "Maximum power: " << max_power << "\n";
+  std::cout << "Coordinates: " << max_x << "," << max_y << "," << max_g << "\n";
+
+  return EXIT_SUCCESS;
+}