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-# Algorithms 2019-2020 Python LEETCODE
-
-Check branches for information.
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+# Binary tree
+
++ [Kth Smallest Element in a BST](#kth-smallest-element-in-a-bst)
+
+## Kth Smallest Element in a BST
+
+https://leetcode.com/problems/kth-smallest-element-in-a-bst/
+
+```python
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+class Solution(object):
+    def in_order_traversal(self, root):
+        if not root: return
+        self.in_order_traversal(root.left)
+        self.list.append(root.val)
+        self.in_order_traversal(root.right)
+
+    def kthSmallest(self, _root, k):
+        """
+        :type _root: TreeNode
+        :type k: int
+        :rtype: int
+        """
+        root = _root
+        if not root: return 0
+
+        self.list = []
+        self.in_order_traversal(root)
+
+        return self.list[k - 1]
+
+```
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