Given a Binary Search Tree (BST) with the root node root
, return the minimum difference between the values of any two different nodes in the tree.
Example :
Input: root = [4,2,6,1,3,null,null] Output: 1 Explanation: Note that root is a TreeNode object, not an array. The given tree [4,2,6,1,3,null,null] is represented by the following diagram: 4 / 2 6 / \ 1 3 while the minimum difference in this tree is 1, it occurs between node 1 and node 2, also between node 3 and node 2.
找BST中任意两节点间的最小差。
根据二叉搜索树的特点,中序遍历就是一组升序数组,最小差值必然在数组中相邻元素中产生。
所以中序遍历一遍二叉树,返回相邻遍历的两个点之间的最小差就好了。
class Solution { private: int temp = INT_MAX; int res = INT_MAX; public: int minDiffInBST(TreeNode* root) { if (root) { if (root->left) minDiffInBST(root->left); if (temp != INT_MAX) res = min(res, root->val - temp); temp = root->val; if (root->right) minDiffInBST(root->right); } return res; } };