Update and rename maxDepth.cpp to maximum-depth-of-binary-tree.cpp

Author: kamyu104

C++/maxDepth.cpp renamed to C++/maximum-depth-of-binary-tree.cpp

@@ -1,5 +1,8 @@
+// Time:  O(n)
+// Space: O(h)
+
 /**
- * Definition for binary tree
+ * Definition for a binary tree node.
  * struct TreeNode {
  *     int val;
  *     TreeNode *left;
@@ -9,9 +12,10 @@
  */
 class Solution {
 public:
-    int maxDepth(TreeNode *root) {
-        if(!root)
+    int maxDepth(TreeNode* root) {
+        if (!root) {
             return 0;
-        return  max(maxDepth(root->left), maxDepth(root->right))+1;
+        }
+        return max(maxDepth(root->left), maxDepth(root->right)) + 1;
     }
 };