题目:原题链接(中等)
标签:树、二叉树、二叉搜索树
| 解法 | 时间复杂度 | 空间复杂度 | 执行用时 | 
| Ans 1 (Python) | O ( l o g 2 N ) | O ( l o g 2 N ) | 超出时间限制 | 
| Ans 2 (Python) | O ( N 1 + N 2 ) | O ( N 1 + N 2 ) | 100ms (68.75%) | 
| Ans 3 (Python) | 
解法一:
class Solution:
    def inorder(self, node, lst):
        if node:
            self.inorder(node.left, lst)
            lst.append(node.val)
            self.inorder(node.right, lst)
    def twoSumBSTs(self, root1: TreeNode, root2: TreeNode, target: int) -> bool:
        lst1, lst2 = [], []
        self.inorder(root1, lst1)
        self.inorder(root2, lst2)
        s1, s2 = len(lst1), len(lst2)
        i1, i2 = 0, s2 - 1
        while i1 < s1 and i2 >= 0:
            val = lst1[i1] + lst2[i2]
            if val < target:
                i1 += 1
            elif val > target:
                i2 -= 1
            else:
                return True
        return False









