Line data    Source code

       1              : #include "Grid2d.h"
       2              : #include "LinewiseInput.h"
       3              : #include "PuzzleImpl.h"
       4              : 
       5              : #include <algorithm>
       6              : #include <string>
       7              : 
       8            1 : template <> std::string solvePart1<2024, 4>(std::string_view const input) {
       9            1 :   LinewiseInput linewise(input);
      10            1 :   Grid2d<char> grid = linewise.makeCharGrid2dWithGhostLayers(3, '.');
      11              : 
      12            1 :   std::array<Grid2d<char>::Coord, 8u> constexpr dirs = {
      13            1 :       {{1, 0}, {0, 1}, {-1, 0}, {0, -1}, {1, 1}, {-1, -1}, {1, -1}, {-1, 1}}};
      14              : 
      15            1 :   std::string_view constexpr word = "XMAS";
      16              : 
      17            1 :   uint64_t count = 0;
      18          141 :   for (Grid2d<char>::Coord c{0, 0}; c.y() < grid.ySize(); ++c.y())
      19        19740 :     for (c.x() = 0; c.x() < grid.xSize(); ++c.x())
      20        19600 :       if (grid[c] == 'X') {
      21        30096 :         count += std::ranges::count_if(dirs, [&](auto const &d) {
      22        49814 :           for (int i = 1; i < 4; ++i)
      23        47267 :             if (grid[c + i * d] != word[i])
      24        27549 :               return false;
      25         2547 :           return true;
      26        30096 :         });
      27         3762 :       }
      28              : 
      29            1 :   return std::to_string(count);
      30            1 : }
      31              : 
      32            1 : template <> std::string solvePart2<2024, 4>(std::string_view const input) {
      33            1 :   LinewiseInput linewise(input);
      34            1 :   Grid2d<char> grid = linewise.makeCharGrid2d();
      35              : 
      36            1 :   uint64_t cnt = 0;
      37          139 :   for (int y = 1; y < grid.ySize() - 1; ++y)
      38        19182 :     for (int x = 1; x < grid.xSize() - 1; ++x)
      39        19044 :       if (grid[x, y] == 'A' &&
      40        19044 :           ((grid[x - 1, y - 1] == 'M' && grid[x + 1, y + 1] == 'S') ||
      41         4865 :            (grid[x - 1, y - 1] == 'S' && grid[x + 1, y + 1] == 'M')) &&
      42        19044 :           ((grid[x - 1, y + 1] == 'M' && grid[x + 1, y - 1] == 'S') ||
      43         2751 :            (grid[x - 1, y + 1] == 'S' && grid[x + 1, y - 1] == 'M'))) {
      44         1939 :         ++cnt;
      45         1939 :       }
      46              : 
      47            1 :   return std::to_string(cnt);
      48            1 : }