leetcode226-翻转二叉树

翻转二叉树

• 递归

class Solution {
    public TreeNode invertTree(TreeNode root) {
        if(root == null)    return root;
        TreeNode l = invertTree(root.left), r = invertTree(root.right);
        root.left = r; root.right = l;
        return root;
    }
}