Add 230_Kth_Smallest_Element_in_a_BST.java

Author: Sean Prashad

Tree Depth First Search/230_Kth_Smallest_Element_in_a_BST.java

@@ -0,0 +1,30 @@
+class Solution {
+ public int kthSmallest(TreeNode root, int k) {
+ if (root == null) {
+ return -1;
+ }
+
+ Stack<TreeNode> stack = new Stack<>();
+ int result = 0;
+
+ while (root != null || !stack.isEmpty()) {
+ while (root != null) {
+ stack.push(root);
+ root = root.left;
+ }
+
+ root = stack.pop();
+
+ k--;
+
+ if (k == 0) {
+ result = root.val;
+ break;
+ }
+
+ root = root.right;
+ }
+
+ return result;
+ }
+}