add Binary Tree Level Order Traversal II C++ solution (kamyu104#74)

* Update README.md

* Update README.md

* Create maximum-subarray.cpp

* Update maximum-subarray.cpp

* Create binary-tree-level-order-traversal-ii.cpp

* Update README.md

Author: ycsheu

C++/binary-tree-level-order-traversal-ii.cpp

@@ -0,0 +1,46 @@
+// Time:  O(n)
+// Space: O(n)
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    vector<vector<int>> levelOrderBottom(TreeNode* root) {
+        vector<vector<int>> result;
+        queue<TreeNode *> que;
+
+        if (root != nullptr) {
+            que.emplace(root);
+        }
+
+        while (!que.empty()) {
+            vector<int> level;
+            int size = que.size();
+            for (int i = 0; i < size; i++) {
+                auto *front = que.front();
+                que.pop();
+                level.emplace_back(front->val);
+                if (front->left != nullptr) {
+                    que.emplace(front->left);
+                }
+                if (front->right != nullptr) {
+                    que.emplace(front->right);
+                }
+            }
+            result.emplace_back(move(level));
+        }
+        
+        // The only difference between binary-tree-level-order-traversal
+        // and binary-tree-level-order-traversal-ii
+        reverse(result.begin(), result.end());
+        
+        return result;
+    }
+};

C++/maximum-subarray.cpp

@@ -5,6 +5,7 @@ class Solution {
 public:
     int maxSubArray(vector<int>& nums) {
         const auto& max_num = *max_element(nums.cbegin(), nums.cend());
+
         if (max_num < 0) {
             return max_num;
         }

README.md

@@ -750,7 +750,7 @@
 |  #  | Title           |  Solution       |  Time           | Space           | Difficulty    | Tag          | Note| 
 |-----|---------------- | --------------- | --------------- | --------------- | ------------- |--------------|-----|
 0102| [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)| [C++](./C++/binary-tree-level-order-traversal.cpp) [Python](./Python/binary-tree-level-order-traversal.py)| _O(n)_| _O(n)_| Easy  || 
-0107| [Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)| [Python](./Python/binary-tree-level-order-traversal-ii.py) | _O(n)_| _O(n)_| Easy  ||
+0107| [Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)| [C++](./C++/binary-tree-level-order-traversal-ii.cpp) [Python](./Python/binary-tree-level-order-traversal-ii.py) | _O(n)_| _O(n)_| Easy  ||
 0103| [Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)| [Python](./Python/binary-tree-zigzag-level-order-traversal.py) | _O(n)_| _O(n)_| Medium  ||  
 0117| [Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/)|[Python](./Python/populating-next-right-pointers-in-each-node-ii.py)| _O(n)_ | _O(1)_ | Hard ||
 0127| [Word Ladder](https://leetcode.com/problems/word-ladder/)|[Python](./Python/word-ladder.py) | _O(n * d)_      | _O(d)_          | Medium         ||