Today's Challenge

https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/

Populating Next Right Pointers in Each Node II - LeetCode

트리는 여전히 어렵다.
동일한 트리 레벨을 표시하도록 구현하면 된다.

class Solution:
    def connect(self, root: 'Node') -> 'Node':
        if not root:
            return None
        
        q = deque()
        q.append(root)
        dummy = Node(-999)
        
        while q:
            length = len(q)
            
            prev = dummy
            
            for _ in range(length):
                popped = q.popleft()
                
                if popped.left:
                    q.append(popped.left)
                    prev.next = popped.left
                    prev = prev.next
                if popped.right:
                    q.append(popped.right)
                    prev.next = popped.right
                    prev = prev.next
        
        return root