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Level Order Traversal of a Binary Tree using Iteration

Visualization

Algorithm Steps

  1. Start with the root node of the binary tree.
  2. If the tree is empty, return an empty result.
  3. Initialize a queue and enqueue the root node.
  4. While the queue is not empty, dequeue a node, record its value, and enqueue its left and right children (if they exist).
  5. Continue until the queue is empty; the recorded values represent the level order traversal.

Level Order Traversal of a Binary Tree using Iteration - Code Examples Code

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class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

def levelOrderTraversal(root):
    if not root:
        return []
    queue = [root]
    result = []
    while queue:
        node = queue.pop(0)
        result.append(node.val)
        if node.left:
            queue.append(node.left)
        if node.right:
            queue.append(node.right)
    return result

if __name__ == '__main__':
    # Construct binary tree:
    #        1
    #       / \
    #      2   3
    #     / \
    #    4   5
    root = TreeNode(1, TreeNode(2, TreeNode(4), TreeNode(5)), TreeNode(3))
    print(levelOrderTraversal(root))