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Binary Tree Level Order Traversal - Leetcode 102 - BFS - Python

Binary Tree Level Order Traversal


Given the root of a binary tree, return the level order traversal of its nodes' values. (i.e., from left to right, level by level).



class Solution:

    def levelOrder(self, root: Optional[TreeNode]) -> List[List[int]]:

        ans = []

        q = collections.deque()

        q.append(root)

        

        while q :

            l = len(q)

            lvl = []

            for i in range(l):

                node = q.popleft()

                if node:

                    lvl.append(node.val)

                    q.append(node.left)

                    q.append(node.right)

            if lvl:

                ans.append(lvl)

        return ans

        

Explaination :








 

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