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题目： Given n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example,Given n = 3, your program should return 阅读全文
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题目： Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n = 3, there are a total of 5 unique 阅读全文
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题目： Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains 阅读全文
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题目要求： Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. 给出一棵二叉树，其中有两个结点交换了位置，要求找出这两个 阅读全文