leetcode 117. 填充每个节点的下一个右侧节点指针 II

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解题思路

按层遍历树即可

代码

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class Solution:
    def connect(self, root: 'Node') -> 'Node':
        if not root:
            return root

        layer_nodes = [root]
        while layer_nodes:
            next_layer_nodes = []
            layer_nodes_len = len(layer_nodes)
            for i, node in enumerate(layer_nodes):
                if i == layer_nodes_len - 1:
                    node.next = None
                else:
                    node.next = layer_nodes[i+1]
                if node.left:
                    next_layer_nodes.append(node.left)
                if node.right:
                    next_layer_nodes.append(node.right)
            layer_nodes = next_layer_nodes
            
        return root