二叉树前序、中序、后序遍历

 

//        function1(root);
//        function2(root);
        function3(root);
    }

    class TreeNode {
        String value;

        TreeNode left;
        TreeNode right;

        TreeNode(String value) {
            this.value = value;
        }
    }

    //根左右
    void function1(TreeNode current) {
        if (current == null) {
            return;
        }

        log(current);

        function1(current.left);

        function1(current.right);
    }

    //左根右
    void function2(TreeNode current) {
        if (current == null) {
            return;
        }

        function2(current.left);

        log(current);

        function2(current.right);
    }

    //左右根
    void function3(TreeNode current) {
        if (current == null) {
            return;
        }

        function3(current.left);
        function3(current.right);
        log(current);
    }

    void log(TreeNode node) {
        if (node != null) {
            Log.i(TAG, node.value);
        }
    }