I can now get into google

Author: tech-cow

README.md

@@ -85,10 +85,11 @@ Success is like pregnancy, Everybody congratulates you but nobody knows how many
 |235|[Lowest Common Ancestor of a Binary Search Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/#/description)| [Python](./tree/Yu/235_lca_bst.py) | _O(N)_| _O(1)_  | Easy | ||
 
 
-## 5/2 Tasks (Tree Easy/Medium)
+## Tree Easy
 |  #  | Title | Solution | Time | Space | Difficulty |Tag| Note|
 |-----|-------| -------- | ---- | ------|------------|---|-----|
 |108|[Convert Sorted Array to Binary Search Tree](https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/#/solutions)| [Python [Yu]](./tree/Yu/108.py) | _O(N)_| _O(N)_  | Easy | |[公瑾讲解](https://www.youtube.com/watch?v=lBrb4fXPcMM)|
+|226|[Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/#/description)| [Python [Yu]](./tree/Yu/226.py) | _O(N)_| _O(1)_  | Easy | |[公瑾讲解](https://youtu.be/oiX3mqcAK0s)|
 |563|[Binary Tree Tilt](https://leetcode.com/problems/binary-tree-tilt/#/description)| [Python [Yu]](./tree/Yu/563.py) | _O(N)_| _O(1)_  | Easy | |[公瑾讲解](https://youtu.be/47FQVP4ynk0)|
 |257|[Binary Tree Paths](https://leetcode.com/problems/binary-tree-paths/#/description)| [Python [Yu]](./tree/Yu/257.py) | _O(N)_| _O(N)_  | Easy | |[公瑾讲解](https://youtu.be/Zr_7qq2f16k)|
 |102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/#/description)| [Python [Yu]](./tree/Yu/102.py) | _O(N)_| _O(N)_  | Medium | |[公瑾讲解](https://youtu.be/IWiprpdSgzg)|

stack_queue/template.py

@@ -2,28 +2,40 @@
 # -*- coding: utf-8 -*-
 
 # Author: Yu Zhou
+# 226. Invert Binary Tree
 
 # ****************
 # Descrption:
-# Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.
-#
-# push(x) -- Push element x onto stack.
-# pop() -- Removes the element on top of the stack.
-# top() -- Get the top element.
-# getMin() -- Retrieve the minimum element in the stack.
+# Invert a binary tree
 # ****************
 
 # 思路：
-# 创建一个额外的stack用来储存所有的最小值
-# 返回Min的时候，就返回minstack的最后一个值就好了
-
+# 每层需要进行左右的互换
+# 完了以后向上返回就行
 
 
 # ****************
 # Final Solution *
 # ****************
-
-
-# ***************************************
-# The following code is an fail attempt *
-# ***************************************
+class Solution(object):
+    def invertTree(self, root):
+        """
+        :type root: TreeNode
+        :rtype: TreeNode
+        """
+
+        #Edge
+        if not root:
+            return
+
+        #Swap
+        temp = root.left
+        root.left = root.right
+        root.right = temp
+
+        #Recusion
+        self.invertTree(root.left)
+        self.invertTree(root.right)
+
+        #Return
+        return root

tree/Yu/226.py

@@ -0,0 +1,41 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+# Author: Yu Zhou
+# 226. Invert Binary Tree
+
+# ****************
+# Descrption:
+# Invert a binary tree
+# ****************
+
+# 思路：
+# 每层需要进行左右的互换
+# 完了以后向上返回就行
+
+
+# ****************
+# Final Solution *
+# ****************
+class Solution(object):
+    def invertTree(self, root):
+        """
+        :type root: TreeNode
+        :rtype: TreeNode
+        """
+
+        #Edge
+        if not root:
+            return
+
+        #Swap
+        temp = root.left
+        root.left = root.right
+        root.right = temp
+
+        #Recusion
+        self.invertTree(root.left)
+        self.invertTree(root.right)
+
+        #Return
+        return root

tree/Yu/try.py

@@ -0,0 +1,6 @@
+def traversal(root):
+  if not root:
+    return None
+  print root.val
+  traversal(root.left)
+  traversal(root.right)

tree/Yu/try2.py

@@ -0,0 +1,77 @@
+# '''
+#     1
+#   /   \
+#  2      3
+# / \     / \
+# 1  3   6   2
+#             \
+#              5
+#
+#              1
+#            /   \
+#           3      2
+#          / \     / \
+#         2   6   3   1
+#        /
+#       5
+
+def inverseTree(root):
+  # if root.left or root.right:
+  temp = root.left
+  root.left = root.right
+  root.right = temp
+
+
+#
+# return 3
+#
+#
+#    2
+#     \
+#      3
+#     /
+#    2
+#   /
+#  1
+#
+# return 2
+#
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+#
+#   2
+#  / \
+# 0   5
+#
+# '''
+#
+#
+#
+#
+# def longestCon(root):
+#     '''
+#     input: TreeNode
+#     output: int
+#     '''
+#     def dfs_level(node, max_num):
+#         if not root:
+#             return 0
+#         cur = 1
+#         left = dfs_level(node.left)
+#         right = dfs_level(node.right)
+#
+#         if node.left:
+#             if node.val + 1 == node.left.val:
+#                 cur = max(cur, left + 1)
+#         if node.right:
+#             if node.val + 1 == node.right.val:
+#                 cur = max(cur, right + 1)
+#         max_num = max(max_num, cur)
+#         return cur
+#
+#     max_num = 0
+#     dfs_level(root, max_num)
+#     return max_num