Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.
Example:
Input:
1
\
3
/
2
Output:
1
Explanation:
The minimum absolute difference is 1, which is the difference between 2 and 1 (or between 2 and 3).
Note: There are at least two nodes in this BST.
BST中序遍歷是有序的既荚。求最小值的時候就是看這個節(jié)點(diǎn)和前邊的節(jié)點(diǎn)的值是不是最小值就行了。
代碼如下：
/**
* 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 getMinimumDifference(TreeNode* root) {
finMinValue(root);
return r;
}
//中序遍歷
void finMinValue(TreeNode* root)
{
if(root == NULL)
return;
finMinValue(root->left);
if(pre != -1)
{
int v = abs(root->val - pre);
if(v < r)
r = v;
}
pre = root->val;
finMinValue(root->right);
}
private:
int r = INT_MAX;
int pre = -1;
};
