打卡群刷题总结0611——区域和检索-数组不可变

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):
    def __init__(self):
        self.res = []

    def gen(node, begin, end, current):
        if begin > end:
            return
        for i in range(begin, end + 1):
            node.val = TreeNode(i)
            gen(node.left, begin, i - 1)
            gen(node.right, i + 1, end)

    def generateTrees(self, n):
        """
        :type n: int
        :rtype: List[TreeNode]
        """
        if n == 1:
            return [[1]]
        root = None
        gen(root, 1, n, [])
        return self.res