binary-trees Swift #8 program

/* The Computer Language Benchmarks Game
   https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
 
   contributed by Isaac Gouy
*/

class Tree {
   var left, right: Tree?

   init (_ left: Tree?, _ right: Tree?) {
      self.left = left
      self.right = right
   }

   static func with (_ depth: Int) -> Tree {
      return (depth == 0) 
         ? Tree (nil, nil)
         : Tree ( with(depth-1), with(depth-1))
   }

   func nodeCount () -> Int {
      return (left == nil)
         ? 1 
         : 1 + left!.nodeCount() + right!.nodeCount()   
   }
   
   func clear () {
      if (left != nil) {
         left?.clear()       
         self.left = nil
         right?.clear()           
         self.right = nil          
      }
   }    
}

func main(_ n: Int) {
   let minDepth = 4  
   let maxDepth = minDepth + 2 > n ? minDepth + 2 : n
   let stretchDepth = maxDepth + 1    
   
   stretch(stretchDepth)
   let longLivedTree = Tree.with(maxDepth)     
   
   for depth in stride(from: minDepth, to: stretchDepth, by: 2){   
      let iterations = 1 << (maxDepth - depth + minDepth)
      var sum = 0         
      for _ in 1...iterations {
         sum += count(depth)
      }      
      print("\(iterations)\t trees of depth \(depth)\t check: \(sum)")       
   }
   let count = longLivedTree.nodeCount()  
   longLivedTree.clear()   
   print("long lived tree of depth \(maxDepth)\t check: \(count)")    
}

func stretch(_ depth: Int) {         
   print("stretch tree of depth \(depth)\t check: \(count(depth))")  
}

func count(_ depth: Int) -> Int {
   let t = Tree.with(depth)         
   let c = t.nodeCount()
   t.clear() 
   return c
}   

main( 
   (CommandLine.argc > 1) 
      ? Int(CommandLine.arguments[1])! 
      : 10 )
    

NOTES:
64-bit Ubuntu quad core
Swift version 6.0
(swift-6.0-RELEASE)
Target: x86_64-unknown-linux-gnu


 Mon, 14 Oct 2024 02:20:09 GMT

MAKE:
/opt/src/swift-6.0-RELEASE/usr/bin/swiftc binarytrees.swift-8.swift -Ounchecked -wmo  -o binarytrees.swift-8.swift_run

13.89s to complete and log all make actions

COMMAND LINE:
 ./binarytrees.swift-8.swift_run 21

PROGRAM OUTPUT:
stretch tree of depth 22	 check: 8388607
2097152	 trees of depth 4	 check: 65011712
524288	 trees of depth 6	 check: 66584576
131072	 trees of depth 8	 check: 66977792
32768	 trees of depth 10	 check: 67076096
8192	 trees of depth 12	 check: 67100672
2048	 trees of depth 14	 check: 67106816
512	 trees of depth 16	 check: 67108352
128	 trees of depth 18	 check: 67108736
32	 trees of depth 20	 check: 67108832
long lived tree of depth 21	 check: 4194303