Method left_subtree

publication/code/chapter08/avl.rs:181–186

获取左右子树

(&mut self)

    // 获取左右子树
    fn left_subtree(&mut self) -> &mut Self {
        match self {
            Null => panic!("Error: Empty tree!"),
            Tree(node) => &mut node.left,
        }
    }

    fn right_subtree(&mut self) -> &mut Self {
        match self {