public class Solution {
	public TreeNode invertTree(TreeNode root) {
		if (root == null)
			return null;
		Queue<TreeNode> queue = new LinkedList<TreeNode>();
		queue.add(root);// 把节点储存在链表里
		while (!queue.isEmpty()) {// 循环
			TreeNode current = queue.remove();// 提取节点
			TreeNode temp = current.left;// 左右交换
			current.left = current.right;
			current.right = temp;
			if (current.left != null)
				queue.add(current.left);
			if (current.right != null)
				queue.add(current.right);
		}
		return root;
	}
}