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Author: kedebug

BinaryTreeLevelOrderTraversalII/BinaryTreeLevelOrderTraversalII.cpp

@@ -0,0 +1,48 @@
+/**
+ * Definition for binary tree
+ * 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) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        
+        vector<vector<int>> result;
+        if (root == NULL) return result;
+        
+        queue<TreeNode*> nodeQueue;
+        vector<int> value;
+        nodeQueue.push(root);
+        int nodeNow = 1;
+        int nodeNext = 0;
+        
+        while (!nodeQueue.empty()) {
+            TreeNode *node = nodeQueue.front();
+            nodeQueue.pop();
+            nodeNow -= 1;
+            value.push_back(node->val);
+            if (node->left) {
+                nodeQueue.push(node->left);
+                nodeNext += 1;
+            }
+            if (node->right) {
+                nodeQueue.push(node->right);
+                nodeNext += 1;
+            }
+            if (nodeNow == 0) {
+                result.push_back(value);
+                value.clear();
+                nodeNow = nodeNext;
+                nodeNext = 0;
+            }
+        }
+        reverse(result.begin(), result.end());
+        return move(result);
+    }
+};