python-leetcode-不同的二叉搜索树II

95. 不同的二叉搜索树 II - 力扣（LeetCode）

# Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=None, right=None): # self.val = val # self.left = left # self.right = right class Solution: def generateTrees(self, n: int) -> List[Optional[TreeNode]]: if n == 0: return [] return self._generate_trees(1, n) def _generate_trees(self, start, end): trees = [] # 如果区间为空，则返回 [None] 作为空树的情况 if start > end: trees.append(None) return trees # 枚举每个数字作为根节点 for i in range(start, end + 1): # 递归生成所有可能的左子树和右子树 left_trees = self._generate_trees(start, i - 1) right_trees = self._generate_trees(i + 1, end) # 将所有左子树和右子树组合起来 for left in left_trees: for right in right_trees: root = TreeNode(i) root.left = left root.right = right trees.append(root) return trees