二叉查找树 Java实现

运行结果：

0 2 3 4 6 6 9 23 50 78
0 2 3 4 6 9 23 50 78
2 3 4 6 9 23 50 78
root is :50
root's successor is :78
root's predecessor is :23
max value is :78
min value is :2