feat:add Solution.cpp for 0107. Binary Tree Level Order Traversal II

Author: Stackingrule

solution/0100-0199/0107.Binary Tree Level Order Traversal II/Solution.cpp

@@ -0,0 +1,20 @@
+class Solution {
+public:
+    vector<vector<int> > levelOrderBottom(TreeNode* root) {
+        if (!root) return {};
+        vector<vector<int>> res;
+        queue<TreeNode*> q{{root}};
+        while (!q.empty()) {
+            vector<int> oneLevel;
+            for (int i = q.size(); i > 0; --i) {
+                TreeNode *t = q.front();
+                q.pop();
+                oneLevel.push_back(t->val);
+                if (t->left) q.push(t->left);
+                if (t->right) q.push(t->right);
+            }
+            res.insert(res.begin(), oneLevel);
+        }
+        return res;
+    }
+};