Print the nodes in a binary tree level-wise

Print the nodes in a binary tree level-wise

December 24, 2023
easy
BFS

Problem #

Print the nodes in a binary tree level-wise. For example, the following should print 1, 2, 3, 4, 5.

  1
 / \
2   3
   / \
  4   5

Solution #

Here is the Python code to print the nodes of a binary tree level-wise:

class Node:
    def __init__(self, key):
        self.left = None
        self.right = None
        self.val = key

def printLevelOrder(root):
    if not root:
        return

    queue = []
    queue.append(root)

    while queue:
        node = queue.pop(0)
        print(node.val, end=", ")

        if node.left:
            queue.append(node.left)
        if node.right:
            queue.append(node.right)

# Driver code
# Creating the binary tree from the example
#       1
#      / \
#     2   3
#        / \
#       4   5

root = Node(1)
root.left = Node(2)
root.right = Node(3)
root.right.left = Node(4)
root.right.right = Node(5)

# Print level order traversal
printLevelOrder(root)

When executed, this code will print the nodes in the binary tree level-wise as 1, 2, 3, 4, 5,.