LeetCode Binary Tree Level Order Traversal II

LeetCode解题之Binary Tree Level Order Traversal II

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原题

实现树的广度优先遍历的倒序遍历，即从最底层依次向上遍历，每一层上的数据按照从左到右的顺序排列。

注意点：

• 无

例子:

输入:

    3   / \  9  20    /  \   15   7

输出:

[  [15,7],  [9,20],  [3]]

解题思路

直接复用了 Binary Tree Level Order Traversal 的代码，只是最后把序列翻转了。

AC源码

# Definition for a binary tree node.class TreeNode(object):    def __init__(self, x):        self.val = x        self.left = None        self.right = Noneclass Solution(object):    def levelOrderBottom(self, root):        """        :type root: TreeNode        :rtype: List[List[int]]        """        result = []        if not root:            return result        curr_level = [root]        while curr_level:            level_result = []            next_level = []            for temp in curr_level:                level_result.append(temp.val)                if temp.left:                    next_level.append(temp.left)                if temp.right:                    next_level.append(temp.right)            result.append(level_result)            curr_level = next_level        result.reverse()        return resultif __name__ == "__main__":    None

欢迎查看我的Github (https://github.com/gavinfish/LeetCode-Python) 来获得相关源码。