get rid of medium

Author: tech-cow

README.md

@@ -113,15 +113,15 @@
 ## Tree Medium
 |  #  | Title | Solution | Time | Space | Video|
 | --- | ----- | -------- | ---- | ----- | ---- |
-|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/#/description)| [Python ](./tree/Yu/144.py) | _O(N)_| _O(N)_  |  |[:tv:](https://youtu.be/cHbdPonjYS0)|
-|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/#/description)| [Python ](./tree/Yu/102.py) | _O(N)_| _O(N)_  |  |[:tv:](https://youtu.be/IWiprpdSgzg)|
-|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/#/description)| [Python ](./tree/Yu/107.py) | _O(N)_| _O(N)_  |  ||
-|515|[Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row/#/description)| [Python ](./tree/Yu/515.py) | _O(N)_| _O(1)_  |  ||
-|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/#/description)| [Python ](./tree/Yu/236.py) | _O(N)_| _O(1)_  |  |[:tv:](https://youtu.be/WqNULaUhPCc)|
-|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/#/description)| [Python ](./tree/Yu/199.py) | _O(N)_| _O(N)_  |  |[:tv:](https://youtu.be/_iKUgRiUYKA)|
-|114|[Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/#/solutions)| [Python ](./tree/Yu/114.py) | _O(N)_| _O(1)_  |  |[:tv:](https://youtu.be/LfKRZ_qCmYQ)|
-|230|[Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/#/description)| [Python ](./tree/Yu/230.py) | _O(N)_| _O(1)_  |  |[:tv:](https://youtu.be/CfNRc82ighw)|
-|582|[Kill Process](https://leetcode.com/problems/kill-process/#/description)| [Python ](./tree/Yu/582.py) | _O(N)_| _O(N)_  |  |[:tv:](https://youtu.be/fKR1n35Sj8s)|
+|144|[Binary Tree Preorder Traversal](https://leetcode.com/problems/binary-tree-preorder-traversal/#/description)| [Python ](./tree/Yu/144.py) | _O(N)_| _O(N)_  |[:tv:](https://youtu.be/cHbdPonjYS0)|
+|102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/#/description)| [Python ](./tree/Yu/102.py) | _O(N)_| _O(N)_  |[:tv:](https://youtu.be/IWiprpdSgzg)|
+|107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/#/description)| [Python ](./tree/Yu/107.py) | _O(N)_| _O(N)_  ||
+|515|[Find Largest Value in Each Tree Row](https://leetcode.com/problems/find-largest-value-in-each-tree-row/#/description)| [Python ](./tree/Yu/515.py) | _O(N)_| _O(1)_  ||
+|236|[Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/#/description)| [Python ](./tree/Yu/236.py) | _O(N)_| _O(1)_ |[:tv:](https://youtu.be/WqNULaUhPCc)|
+|199|[Binary Tree Right Side View](https://leetcode.com/problems/binary-tree-right-side-view/#/description)| [Python ](./tree/Yu/199.py) | _O(N)_| _O(N)_  |[:tv:](https://youtu.be/_iKUgRiUYKA)|
+|114|[Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list/#/solutions)| [Python ](./tree/Yu/114.py) | _O(N)_| _O(1)_  |[:tv:](https://youtu.be/LfKRZ_qCmYQ)|
+|230|[Kth Smallest Element in a BST](https://leetcode.com/problems/kth-smallest-element-in-a-bst/#/description)| [Python ](./tree/Yu/230.py) | _O(N)_| _O(1)_  |[:tv:](https://youtu.be/CfNRc82ighw)|
+|582|[Kill Process](https://leetcode.com/problems/kill-process/#/description)| [Python ](./tree/Yu/582.py) | _O(N)_| _O(N)_  | [:tv:](https://youtu.be/fKR1n35Sj8s)|
 
 
 ## Backtrack Medium