Berkeley CS 61B Data Structures(in Java) Homework4 加分+讨论帖

打卡，经历了Project1四个part的洗礼之后，感觉这种homework已经无所畏惧了

感谢第一页的人给的启发，挣扎下完成作业了

参考了楼里同学的想法。多谢楼主的testcode，希望自己以后也能写出这么好的testcode。最后明白了LockList只需要将newNode变成LockListNode也就是加上自身的功能就可以了。所以只需要修改newNode这样每一个新建的Node都带有lock与否的变量。
另外修改remove，添加lockNode。
还学会了怎么调用super的函数。
也更了解了package的概念以及protected，private 和public的区别。

学到了instanceof。。。发现自己小毛病特别多，容易忘记大小写。。

一开始没搞明白第三问什么意思，非常感谢楼上几位同学的分析终于弄出来了。 看来多态继承的理解还不到位

感谢第一页同学们的指点和帮助，半知半解地也算是做出来了。做override的过程中，发现自己已经完全忘了super的用法，顺便重新巩固了一下

时隔大半个月做作业……发现版主早就不打分了，就懒得贴图了。。打卡笔记。。。
求问解释一下partII？怎么样破坏DList里的invariant?

1. DList的构造函数忘记设置head, 导致NullPointerException。
1. override2个函数。newNode()里把所有DListNode标记成LockDListNode，DList的所有函数即可继承。

继承这个概念挺好理解的但是实际操作起来其实还有点困难
这个作业真的特别好 让我对继承多态又有了更深的理解

除了好多问题，看了别人的代码菜终于找到bug，自己对继承了解不够，打算找本书继续看一下。

Now we are testing DList.
Here is a list after insertBack 6, 9, 12: [  6  9  12  ]

Here is the same list after insertBack(15) and insertFront(3): [  3  6  9  12  15  ]

front() should be 3. It is: 3
front's next should be 6. It is: 6
front's next's prev should be 3. It is: 3
After remove the front, the front() should be 6. It is: 6
After insertBefore() and insertAfter(), The first 3 nodes should be 5,6,8. The list is: [  5  6  8  9  12  15  ]

Here is a list after construction: [  ]
isEmpty() should be true. It is: true
length() should be 0. It is: 0
Here is a list after insertFront(3) to an empty list: [  3  ]
Here is a list after insertBack(5) on an empty list: [  5  ]

Here is a list after insertFront 3, 2, 1: [  1  2  3  ]
isEmpty() should be false. It is: false
length() should be 3. It is: 3
Here is the same list after insertBack(4): [  1  2  3  4  ]

Here is a list after insertBack 6, 7: [  6  7  ]
isEmpty() should be false. It is: false
length() should be 2. It is: 2
Here is the same list after insertFront(5): [  5  6  7  ]

Process finished with exit code 0
==========================================

Now we are testing LockDList.
Here is a list after insertBack 6, 9, 12: [  6  9  12  ]

Here is the same list after insertBack(15) and insertFront(3): [  3  6  9  12  15  ]

front() should be 3. It is: 3
front's next should be 6. It is: 6
front's next's prev should be 3. It is: 3
We lockNode front()= 3
After remove the locked front, the front() should still be 3. It is: 3
After remove the back, the back() should be 12. It is: 12
After insertBefore(3) and insertAfter(3), The first 3 nodes should be 5,3,8. The list is: [  5  3  8  6  9  12  ]

Here is a list after construction: [  ]
isEmpty() should be true. It is: true
length() should be 0. It is: 0
Here is a list after insertFront(3) to an empty list: [  3  ]
Here is a list after insertBack(5) on an empty list: [  5  ]

Here is a list after insertFront 3, 2, 1: [  1  2  3  ]
isEmpty() should be false. It is: false
length() should be 3. It is: 3
Here is the same list after insertBack(4): [  1  2  3  4  ]

Here is a list after insertBack 6, 7: [  6  7  ]
isEmpty() should be false. It is: false
length() should be 2. It is: 2
Here is the same list after insertFront(5): [  5  6  7  ]

Process finished with exit code 0