add language type for README code

Author: P-ppc

algorithms/BinaryTreeInorderTraversal/README.md

@@ -1,6 +1,6 @@
 # Binary Tree Inorder Traversal
 Use recursion can easy to solve this problem, like below:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):

algorithms/BinaryTreePostorderTraversal/README.md

@@ -1,6 +1,6 @@
 # Binary Tree Postorder Traversal
 Use recursion can easy to solve this problem, like below:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):

algorithms/BinaryTreePreorderTraversal/README.md

@@ -1,6 +1,6 @@
 # Binary Tree Preorder Traversal
 Use recursion can easy to solve this problem, like below:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):

algorithms/ClimbingStairs/README.md

@@ -1,6 +1,6 @@
 # Climbing Stairs
 This problem is easy to solve by recursive like below:
-```
+```python
 class Solution(object):
     def climbStairs(self, n):
         """

algorithms/ConvertBstToGreaterTree/README.md

@@ -1,6 +1,6 @@
 # Convert Bst To Greater Tree
 We can simply inorder traversal the tree and reverse the result then get sum, just like below:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):

algorithms/LetterCasePermutation/README.md

@@ -1,6 +1,6 @@
 # Letter Case Permutation
 This problem is easy to solve by set, or use Backtracking Algorithm to solve it, just like below:
-```
+```python
 class Solution(object):
     def letterCasePermutation(self, S):
         """

algorithms/MaximumDepthOfBinaryTree/README.md

@@ -1,6 +1,6 @@
 # Maximum Depth Of Binary Tree
 We can use recursion to solve this problem, like this:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):

algorithms/MinCostClimbingStairs/README.md

@@ -1,6 +1,6 @@
 # Min Cost Climbing Stairs
 This problem is easy to solve by dynamic programming, the recursion solution is like below:
-```
+```python
 class Solution(object):
     def minCostClimbingStairs(self, cost):
         """

algorithms/PowerOfFour/README.md

@@ -1,6 +1,6 @@
 # Power Of Four
 Use recursion can easy to solve this problem, like below:
-```
+```python
 class Solution(object):
     def isPowerOfFour(self, num):
         """

algorithms/ReverseLinkedList/README.md

@@ -1,6 +1,6 @@
 # Reverse Linked List
 This problem is easy to solve, the loop solution is like below:
-```
+```python
 # Definition for singly-linked list.
 # class ListNode(object):
 #     def __init__(self, x):

algorithms/SymmetricTree/README.md

@@ -1,6 +1,6 @@
 # Symmetric Tree
 This problem is easy to solve, the recursive solution is like below:
-```
+```python
 # Definition for a binary tree node.
 # class TreeNode(object):
 #     def __init__(self, x):