LeetCode530. Minimum Absolute Difference in BST

一、题目

Given the root of a Binary Search Tree (BST), return the minimum absolute difference between the values of any two different nodes in the tree.

Example 1:

Input: root = [4,2,6,1,3]
Output: 1
Example 2:

Input: root = [1,0,48,null,null,12,49]
Output: 1

Constraints:

The number of nodes in the tree is in the range [2, 104].
0 <= Node.val <= 105

Note: This question is the same as 783: https://leetcode.com/problems/minimum-distance-between-bst-nodes/

二、题解

中序遍历+双指针

/*** Definition for a binary tree node.* struct TreeNode {*     int val;*     TreeNode *left;*     TreeNode *right;*     TreeNode() : val(0), left(nullptr), right(nullptr) {}*     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}*     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}* };*/
class Solution {
public:int res = INT_MAX;TreeNode* pre = nullptr;//中序遍历，比较两个指针的差值void traversal(TreeNode* cur){if(!cur) return;traversal(cur->left);if(pre) res = min(res,cur->val - pre->val);pre = cur;traversal(cur->right);}int getMinimumDifference(TreeNode* root) {traversal(root);return res;}
};