摘要：
Given a binary tree, return the sum of values of nodes with even-valued grandparent. (A grandparent of a node is the parent of its parent, if it exist 阅读全文
摘要：
Given two binary search trees root1 and root2. Return a list containing all the integers from both trees sorted in ascending order. Example 1: Input: 阅读全文
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1323. Maximum 69 Number Easy 56289Add to ListShare Given a positive integer num consisting only of digits 6 and 9. Return the maximum number you can g 阅读全文
摘要：
Given a binary search tree, return a balanced binary search tree with the same node values. A binary search tree is balanced if and only if the depth 阅读全文