diff --git a/src/main/java/leetcode/editor/cn/KthSmallestElementInABst.java b/src/main/java/leetcode/editor/cn/KthSmallestElementInABst.java
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+//给定一个二叉搜索树的根节点 root ，和一个整数 k ，请你设计一个算法查找其中第 k 个最小元素（从 1 开始计数）。 
+//
+// 
+//
+// 示例 1： 
+//
+// 
+//输入：root = [3,1,4,null,2], k = 1
+//输出：1
+// 
+//
+// 示例 2： 
+//
+// 
+//输入：root = [5,3,6,2,4,null,null,1], k = 3
+//输出：3
+// 
+//
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 树中的节点数为 n 。 
+// 1 <= k <= n <= 104 
+// 0 <= Node.val <= 104 
+// 
+//
+// 
+//
+// 进阶：如果二叉搜索树经常被修改（插入/删除操作）并且你需要频繁地查找第 k 小的值，你将如何优化算法？ 
+// Related Topics 树 二分查找 
+// 👍 397 👎 0
+
+package leetcode.editor.cn;
+
+import com.code.leet.entiy.TreeNode;
+
+import java.util.ArrayList;
+import java.util.List;
+
+//230:二叉搜索树中第K小的元素
+public class KthSmallestElementInABst {
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new KthSmallestElementInABst().new Solution();
+    }
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+
+    /**
+     * Definition for a binary tree node.
+     * public class TreeNode {
+     * int val;
+     * TreeNode left;
+     * TreeNode right;
+     * TreeNode() {}
+     * TreeNode(int val) { this.val = val; }
+     * TreeNode(int val, TreeNode left, TreeNode right) {
+     * this.val = val;
+     * this.left = left;
+     * this.right = right;
+     * }
+     * }
+     */
+    class Solution {
+
+        public int kthSmallest(TreeNode root, int k) {
+            List<Integer> nums = getList(root, new ArrayList<>());
+            return nums.get(k - 1);
+        }
+
+        private List<Integer> getList(TreeNode root, List<Integer> list) {
+            if (root == null) {
+                return list;
+            }
+            getList(root.left, list);
+            list.add(root.val);
+            getList(root.right, list);
+
+            return list;
+        }
+    }
+//leetcode submit region end(Prohibit modification and deletion)
+
+}
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diff --git a/src/main/java/leetcode/editor/cn/KthSmallestElementInABst.md b/src/main/java/leetcode/editor/cn/KthSmallestElementInABst.md
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+<p>给定一个二叉搜索树的根节点 <code>root</code> ，和一个整数 <code>k</code> ，请你设计一个算法查找其中第 <code>k</code><strong> </strong>个最小元素（从 1 开始计数）。</p>
+
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/01/28/kthtree1.jpg" style="width: 212px; height: 301px;" />
+<pre>
+<strong>输入：</strong>root = [3,1,4,null,2], k = 1
+<strong>输出：</strong>1
+</pre>
+
+<p><strong>示例 2：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2021/01/28/kthtree2.jpg" style="width: 382px; height: 302px;" />
+<pre>
+<strong>输入：</strong>root = [5,3,6,2,4,null,null,1], k = 3
+<strong>输出：</strong>3
+</pre>
+
+<p> </p>
+
+<p> </p>
+
+<p><strong>提示：</strong></p>
+
+<ul>
+	<li>树中的节点数为 <code>n</code> 。</li>
+	<li><code>1 <= k <= n <= 10<sup>4</sup></code></li>
+	<li><code>0 <= Node.val <= 10<sup>4</sup></code></li>
+</ul>
+
+<p> </p>
+
+<p><strong>进阶：</strong>如果二叉搜索树经常被修改（插入/删除操作）并且你需要频繁地查找第 <code>k</code> 小的值，你将如何优化算法？</p>
+<div><div>Related Topics</div><div><li>树</li><li>二分查找</li></div></div>\n<div><li>👍 397</li><li>👎 0</li></div>
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