[leetcode] 226. Invert Binary Tree 解题报告

要弄懂final关键字的含义

此题不加也行

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