Added KSmallest element in BST

01. DataStructures/04. Tree/Leetcode Questions/Kth Smallest Element in a BST/KSmallest.java

@@ -0,0 +1,40 @@
+/**
+ * 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 {
+
+ int counter = 0;
+ public int kthSmallest(TreeNode root, int k) {
+ return KSmallest(root, k);
+ }
+
+ int KSmallest(TreeNode root, int k) {
+
+ if(root == null)
+ return -1;
+
+
+ int left = KSmallest(root.left, k);
+
+ counter++;
+ if(counter == k)
+ return root.val;
+
+ int right = KSmallest(root.right, k);
+ if(left != -1)
+ return left;
+ return right;
+ }
+}

01. DataStructures/04. Tree/Leetcode Questions/Kth Smallest Element in a BST/README.md

@@ -0,0 +1,9 @@
+Given the root of a binary search tree, and an integer k, return the kth smallest value (1-indexed) of all the values of the nodes in the tree.
+
+
+
+Example 1:
+
+
+Input: root = [3,1,4,null,2], k = 1
+Output: 1