# contributed by Jean Privat
class TreeNode
- var _left: nullable TreeNode
- var _right: nullable TreeNode
- var _item: Int
+ var left: nullable TreeNode
+ var right: nullable TreeNode
+ var item: Int
init(left: nullable TreeNode, right: nullable TreeNode, item: Int)
var depth = min_depth
while depth <= max_depth do
- var iterations = 1.lshift(max_depth - depth + min_depth)
+ var iterations = 1 << (max_depth - depth + min_depth)
var check_res = 0
for i in [1..(iterations+1)[ do