Create 545.Boundary of Binary Tree.cpp

Tree/545.Boundary-of-Binary-Tree/545.Boundary of Binary Tree.cpp

@@ -0,0 +1,85 @@
+/**
+ * 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<int> boundaryOfBinaryTree(TreeNode* root) 
+    {
+        vector<int>results;
+        if (root==NULL) return results;
+
+        results.push_back(root->val);
+
+        vector<int>Left;
+        if (root->left!=NULL)
+        {
+            GoLeft(root->left,Left);
+            Left.pop_back();
+        }
+
+        vector<int>Bottom;
+        if (root->left!=NULL || root->right!=NULL)
+            GoBottom(root,Bottom);
+
+        vector<int>Right;
+        if (root->right!=NULL)
+        {
+            GoRight(root->right,Right);
+            Right.pop_back();
+        }
+        reverse(Right.begin(),Right.end());
+
+        for (int i=0; i<Left.size(); i++)
+            results.push_back(Left[i]);
+
+        for (int i=0; i<Bottom.size(); i++)
+            results.push_back(Bottom[i]);
+
+        for (int i=0; i<Right.size(); i++)
+            results.push_back(Right[i]);    
+
+        return results;
+    }
+
+    void GoLeft(TreeNode* root, vector<int>& Left)
+    {
+        if (root==NULL) return;
+
+        Left.push_back(root->val);
+        if (root->left!=NULL)
+            GoLeft(root->left,Left);
+        else if (root->right!=NULL)
+            GoLeft(root->right,Left);
+    }
+
+    void GoRight(TreeNode* root, vector<int>& Right)
+    {
+        if (root==NULL) return;
+
+        Right.push_back(root->val);
+        if (root->right!=NULL)
+            GoRight(root->right,Right);
+        else if (root->left!=NULL)
+            GoRight(root->left,Right);
+    }    
+
+    void GoBottom(TreeNode* root, vector<int>& Bottom)
+    {
+        if (root==NULL) return;
+        if (root->left==NULL && root->right==NULL)
+        {
+            Bottom.push_back(root->val);
+        }
+        else
+        {
+            GoBottom(root->left,Bottom);
+            GoBottom(root->right,Bottom);
+        }
+    }
+};