Invert-Binary-Tree.py

## Python Solution 1:
# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def invertTree(self, root: TreeNode) -> TreeNode:
        if root == None:
            return root
        temp = root.left
        root.left = self.invertTree(root.right)
        root.right = self.invertTree(temp)
        return root
## Python Solution 2:
class Solution:
    def invertTree(self, root: TreeNode) -> TreeNode:
            if not root:
                return root
            # 将二叉树中的节点逐层放入队列中，再迭代处理队列中的元素
            queue = [root]
            while queue:
                # 每次都从队列中拿一个节点，并交换这个节点的左右子树
                tmp = queue.pop(0)
                tmp.left,tmp.right = tmp.right,tmp.left
                # 如果当前节点的左子树不为空，则放入队列等待后续处理
                if tmp.left:
                    queue.append(tmp.left)
                # 如果当前节点的右子树不为空，则放入队列等待后续处理	
                if tmp.right:
                    queue.append(tmp.right)
            # 返回处理完的根节点
            return root