Write a function to print spiral order traversal of a tree. For below tree, function should print 1, 2, 3, 4, 5, 6, 7.
We have discussed naive approach and two stack based approach in Level Order with recursion and multiple stacks
The idea behind this approach is first we have to take a queue, a direction flag and a separation flag which is NULL
- Insert the root element into the queue and again insert NULL into the queue.
- For every element in the queue insert its child nodes.
- If a NULL is encountered then check the direction to traverse the particular level is left to right or right to left. If it’s an even level then traverse from left to right otherwise traverse the tree in right to level order i.e., from the front to the previous front i.e., from the current NULL to to the last NULL that has been visited. This continues till the last level then there the loop breaks and we print what is left (that has not printed) by checking the direction to print.
Following is the C++ implementation of the explanation
1 2 3 4 5 6 7
Time Complexity: O(n)
Auxiliary Space : O(2*n) = O(n)
- Level order traversal in spiral form | Using one stack and one queue
- Print a Binary Tree in Vertical Order | Set 3 (Using Level Order Traversal)
- Level Order Tree Traversal
- Given level order traversal of a Binary Tree, check if the Tree is a Min-Heap
- Perfect Binary Tree Specific Level Order Traversal
- Perfect Binary Tree Specific Level Order Traversal | Set 2
- Level order traversal line by line | Set 3 (Using One Queue)
- General Tree (Each node can have arbitrary number of children) Level Order Traversal
- Check if the given array can represent Level Order Traversal of Binary Search Tree
- Connect Nodes at same Level (Level Order Traversal)
- Construct BST from its given level order traversal
- Reverse Level Order Traversal
- Level order traversal in spiral form
- Level order traversal with direction change after every two levels
- Check if two trees are mirror of each other using level order traversal
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.