binary-trees Go program

/* The Computer Language Benchmarks Game
 * https://salsa.debian.org/benchmarksgame-team/benchmarksgame/
 *
 * contributed by The Go Authors.
 * based on C program by Kevin Carson
 * flag.Arg hack by Isaac Gouy
 * *reset*
 */

package main

import (
   "flag"
   "fmt"
   "strconv"
)

var n = 0

type Node struct {
     left, right   *Node
}

func  bottomUpTree(depth int) *Node {
   if depth <= 0 {
      return &Node{}
   }
   return &Node{ bottomUpTree(depth-1), bottomUpTree(depth-1) }
}

func (n *Node) itemCheck() int {
   if n.left == nil {
      return 1
   }
   return 1 + n.left.itemCheck() + n.right.itemCheck()
}

const minDepth = 4

func main() {
   flag.Parse()
   if flag.NArg() > 0 { n,_ = strconv.Atoi( flag.Arg(0) ) }

   maxDepth := n
   if minDepth + 2 > n {
      maxDepth = minDepth + 2
   }
   stretchDepth := maxDepth + 1

   check := bottomUpTree(stretchDepth).itemCheck()
   fmt.Printf("stretch tree of depth %d\t check: %d\n", stretchDepth, check)

   longLivedTree := bottomUpTree(maxDepth)

   for depth := minDepth; depth <= maxDepth; depth+=2 {
      iterations := 1 << uint(maxDepth - depth + minDepth)
      check = 0

      for i := 1; i <= iterations; i++ {
         check += bottomUpTree(depth).itemCheck()
      }
      fmt.Printf("%d\t trees of depth %d\t check: %d\n", iterations, depth, check)
   }
   fmt.Printf("long lived tree of depth %d\t check: %d\n", maxDepth, longLivedTree.itemCheck())
}
    

NOTES:
64-bit Ubuntu quad core
go version go1.14 linux/amd64


Wed, 06 May 2020 00:49:21 GMT

MAKE:
/opt/src/go1.14.linux-amd64/go/bin/go build -o binarytrees.go_run

5.42s to complete and log all make actions

COMMAND LINE:
./binarytrees.go_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