print level wise nodes in the binary tree (Breadth First Traversal)

This can be achieved using breadth first traversal algorithm.
– push level wise nodes into the queue at every iteration
– pop the node from queue at every iteration and print its value

Lets look at example:

    15              25
12      18      22      28

BFS puts this tree in queue such there level wise nodes are placed one-another like this

	20 | 15 | 25 | 12 | 18 | 22 | 28

And at every loop element from queue is removed in FIFO manner

	public void breadthFirstNonRecursive() {
		Queue<BinaryNode> queue = new java.util.LinkedList<BinaryNode>();
		while (!queue.isEmpty()) {
			BinaryNode node = queue.poll();
			if (node.left != null)
			if (node.right != null)

Output: 20, 15, 25, 12, 18, 22, 28

3 Responses to print level wise nodes in the binary tree (Breadth First Traversal)

  1. Pingback: algorithm to find left view and right view of binary tree in java | java tech stack

  2. cpanel vps says:

    Thanks very nice blog!|

  3. lprabak says:

    On the same tree output, I want to reverse the elements at each level and print. Eg. 12,18,22,28 are in level 2 ,I want to reverse and print as, 28,22,18,12 . Simillarly for Level 1 to be printed as, “25,15”, . Do you have solution for this.

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