1 files changed, 8 insertions, 51 deletions

diff --git a/src/day23.cpp b/src/day23.cpp
index 207a62c..d8c20d3 100644
--- a/src/day23.cpp
+++ b/src/day23.cpp
@@ -110,58 +110,14 @@ get_neighbours2(const vector<string>& maze, position_t possition)
 }
 
 void
-part1(const vector<string>& maze)
-{
-        const position_t start = { 0, maze[0].find('.') };
-        const position_t end   = { maze.size() - 1, maze[maze.size() - 1].find('.') };
-
-        queue<tuple<position_t, set<position_t>>> queue;
-
-        queue.emplace(start, set<position_t>{});
-
-        size_t longest = 0;
-        while ( !queue.empty() ) {
-                auto [current_position, seen] = queue.front();
-                queue.pop();
-
-                while ( current_position != end ) {
-                        seen.emplace(current_position);
-
-                        const auto neighbours = get_neighbours(maze, current_position);
-
-                        vector<position_t> next_positions;
-
-                        // { neighbours \ seen }
-                        set_difference(neighbours.begin(), neighbours.end(),
-                                       seen.begin(), seen.end(),
-                                       back_inserter(next_positions));
-
-                        if ( next_positions.empty() ) {
-                                break;
-                        }
-
-                        current_position = next_positions[0];
-
-                        for ( size_t idx = 1; idx != next_positions.size(); ++idx ) {
-                                queue.emplace(next_positions[idx], seen);
-                        }
-                }
-                if ( current_position == end ) {
-                        longest = max(longest, seen.size());
-                }
-        }
-        cout << longest << endl;
-}
-
-void
-part2(const vector<string>& maze)
+solve(const vector<string>& maze, function<set<position_t>(const vector<string>&, position_t)> neighbours)
 {
         const position_t start = { 0, maze[0].find('.') };
         const position_t end   = { maze.size() - 1, maze[maze.size() - 1].find('.') };
 
         vector<vector<bool>> visited(maze.size(), vector<bool>(maze[0].size()));
 
-        function<long(position_t, long)> findmax = [&](position_t position, long current) -> long {
+        function<long(position_t, long)> find_longest_path = [&](position_t position, long current) -> long {
                 const auto [row, col] = position;
 
                 if ( visited[row][col] ) {
@@ -173,16 +129,17 @@ part2(const vector<string>& maze)
                 }
 
                 long value = 0;
+
                 visited[row][col] = true;
-                for ( const auto& neighbour: get_neighbours2(maze, position) ) {
-                        value = max(value, findmax(neighbour, current + 1));
+                for ( const auto& neighbour: neighbours(maze, position) ) {
+                        value = max(value, find_longest_path(neighbour, current + 1));
                 }
                 visited[row][col] = false;
 
                 return value;
         };
 
-        auto value = findmax(start, 0);
+        auto value = find_longest_path(start, 0);
         cout << value << endl;
 }
 
@@ -190,6 +147,6 @@ int
 main()
 {
         const auto maze = read_file("data/day23.txt");
-        part1(maze);
-        part2(maze);
+        solve(maze, get_neighbours);
+        solve(maze, get_neighbours2);
 }