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. 求二叉搜索树任意两节点之间的差值，要求最小 C++（4ms）：
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int res = INT_MAX ;
int pre = - ;
int minDiffInBST(TreeNode* root) {
if (root->left != NULL)
minDiffInBST(root->left) ;
if (pre >= )
res = min(res , root->val - pre) ;
pre = root->val ;
if (root->right != NULL)
minDiffInBST(root->right) ;
return res ;
}
};