Merge pull request #379 from ys13579/master

Update treetaversal.cpp

Author: probot-auto-merge[bot]

Tree Traversal/C++/treetaversal.cpp

@@ -92,6 +92,53 @@ void printLevelOrder(Node *root)
             q.push(node->right); 
     } 
 } 
+
+/* Given a binary tree, print its nodes in Levelorder in spiral form*/
+void printLevelOrderSpiral(Node *root) 
+{ 
+    // Base Case 
+    if (root == NULL)  return; 
+  
+    // Create two empty stacks 
+    stack<Node *> s1;
+    stack<Node *> s2; 
+    
+    // Push Root in s1 
+    s1.add(root);
+    
+    while (!s1.empty() || !s2.empty()) 
+    { 
+        //Print nodes of current level from s1 and push nodes of next level to s2
+        while (!s1.empty()) { 
+        Node *node = s1.top();
+        s1.pop();
+        cout << node->data << " ";
+          
+        //Node that is right is pushed before left
+        if (temp->right) 
+            s2.push(temp->right); 
+        if (temp->left) 
+            s2.push(temp->left);
+          
+        }
+  
+        //Print nodes of current level from s2 and push nodes of next level to s1
+        while (!s2.empty()) { 
+        Node *node = s2.top();
+        s2.pop();
+        cout << node->data << " ";
+          
+        //Node that is right is pushed before left
+        if (temp->right) 
+            s1.push(temp->right); 
+        if (temp->left) 
+            s1.push(temp->left);
+          
+        } 
+    } 
+} 
+
+
 
 /* Driver program to test above functions*/
 int main() 
@@ -113,6 +160,9 @@ int main()
 
     cout << "Level Order traversal of binary tree is \n"; 
     printLevelOrder(root); 
+  
+    cout << "Level Order traversal in Spiral form of binary tree is \n";
+    printLevelOrderSpiral(root); 
 
     return 0; 
 }