# Level order traversal of a binary tree in python.

Binary tree are the tree where one node can have only two child and cannot have more than two.

## Level order traversal of a binary tree.

Level order traversal means that we visit the nodes level by level. Like for below tree the level order traversal will be

Its Level order traversal will be

1 2 3 4 5

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Here is the code for doing that.

```class Node:

def __init__(self,data):

self.left = None

self.right = None

self.data = data

def level_order(queue):

if len(queue) == 0:

return

node = queue[0]

queue.pop(0)

if node.left:

queue.append(node.left)

if node.right:

queue.append(node.right)

print node.data

level_order(queue)

queue = list()

root = Node(1)

queue.append(root)

root.left = Node(2)

root.right = Node(3)

root.left.left = Node(4)

root.left.right = Node(5)

level__order(queue)

# 1 2 3 4 5 ```

Length of Longest Increasing Subsequence (LIS) in python [Dynamic Programming]

### What we did here:

We make use of queues to do the level order traversal. What we did is we visit a node and put its left and right child in the queue and delete the current node. In this way we visit the tree in level order.

Algorithms: Mirror a Binary tree using python