【leetCode】Binary Tree Level Order Traversal python实现

Binary Tree Level Order Traversal

原题链接

Binary Tree Level Order Traversal

---

实现原理解析

层次遍历即可

python代码实现

class Solution(object):
    def __init__(self):
        self.result = []

    def levelOrder(self, root):
        """
        :type root: TreeNode
        :rtype: List[List[int]]
        """
        if root is None:
            return []
        else:
            rootLevel =[root]
            self.result.append(rootLevel)
            self.levelSearch(rootLevel)
        ret = []
        for eachLevel in self.result:
            ret.append([each.val for each in eachLevel])
        return ret


    def levelSearch(self, upLevelNodes):
        """
        :param upLevelNodes:
        :return:
        """
        ret = []
        if len(upLevelNodes) == 0:
            self.result.pop()
            return
        for eachNode in upLevelNodes:
            if eachNode.left is not None:
                ret.append(eachNode.left)
            if eachNode.right is not None:
                ret.append(eachNode.right)
        if len(ret) == 0:
            return
        self.result.append(ret)
        self.levelSearch(ret)