愛比的新手筆記

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:Taiwan is a country. 臺灣是我的國家

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

先參考[LeetCode] 144. Binary Tree Preorder Traversal 將TreeNode轉成List再算

public class Solution {
        public int GetMinimumDifference(TreeNode root)
        {
            List<int> lst = new List<int>();
            GetValue(root, lst);
            lst.Sort();
            int i = lst.Count - 1;
            int min = lst[i];
            for (; i > 0;)
                min = Math.Min(lst[i] - lst[--i], min);
            return min;
        }
        private void GetValue(TreeNode root, List<int> lst)
        {
            if (root != null)
            {
                lst.Add(root.val);
                GetValue(root.left, lst);
                GetValue(root.right, lst);
            }
        }
}

Taiwan is a country. 臺灣是我的國家