code: function leftInorder(n, x) {
    if(n <= 0) {
      return 0
    }
    var r = rootInorder(n)
    if(x > r) {
      return leftInorder(n-r-1, x-r-1) + r + 1
    } else if(x === r) {
      return rootInorder(x)
    }
    return leftInorder(r, x)
  
  }
docs: Again, we get screwed because n is not a power of two -1.  If it was, we could do:  left = x - (1 << (h-1) )  Where h is the height of the node