429. N-ary Tree Level Order Traversal

429. N-ary Tree Level Order Traversal

可以先做這題 116. Populating Next Right Pointers in Each Node

"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""

class Solution:
    def levelOrder(self, root: 'Node') -> List[List[int]]:
        if not root:
            return root
        queue = deque([root])
        ans = []
        level = 0
        while queue:
            size = len(queue)
            ans.append([])
            
            for i in range(size):
                node = queue.popleft()
                ans[level].append(node.val)
                for child in node.children:
                    queue.append(child)
            level += 1
        return ans

"""
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""

class Solution:
    def levelOrder(self, root: 'Node') -> List[List[int]]:
        if not root:
            return root
        queue = deque([root])
        ans = defaultdict(list)
        level = 0
        while queue:
            size = len(queue)
            for i in range(size):
                node = queue.popleft()
                ans[level].append(node.val)
                for child in node.children:
                    queue.append(child)
            level += 1
        return ans.values()