Added problem Kth smallest in BST

Graph Algorithms/KthSmallestInBST.py

@@ -0,0 +1,29 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+def traverse(root, k):
+    global index, res 
+    if not root:
+        # index += 1
+        return None
+
+    traverse(root.left, k)
+
+    index += 1
+    if index == k:
+        res = root.val
+    # print(index, root.val)
+
+    traverse(root.right, k)
+
+index = 0
+res = None
+class Solution:
+    def kthSmallest(self, root: Optional[TreeNode], k: int) -> int:
+        global index, res
+        index= 0
+        traverse(root, k)
+        return res