more debugging printouts

day16/d16p1.swift

@@ -58,8 +58,8 @@ struct Maze : CustomStringConvertible {
         let s: [[String]] = walls.enumerated().map { i, r in
             [String(format: "%3d ", i)] + r.map { $0 ? "██" : "  " }
         }
-        print("    " + (0..<w).map { " \($0 % 10)" }.joined())
-        return s.map { $0.joined() }.joined(separator: "\n")
+        return ("    " + (0..<w).map { " \($0 % 10)" }.joined()) +
+            s.map { $0.joined() }.joined(separator: "\n")
     }
     init(fromFile f: String) throws {
         let content = try String(contentsOfFile: f, encoding: .ascii)

day16/d16p2.swift

@@ -146,6 +146,7 @@ struct AoC {
     static func main() throws {
         let maze = try Maze(fromFile: CommandLine.arguments[1])
         let (graph, pathPairs) = maze.graph()
+        print("maze: \(maze.w)x\(maze.h) intersections: \(graph.count)")
         let visited = search(graph: graph, start: maze.start)
         let minCost = maze.ends.compactMap { visited[$0] }.map { $0.0 }.min()!
         print("minCost: \(minCost)")