• ### Leetcode – Remove Nth Node From End of List (Java)

Remove Nth Node From End of List

Given a linked list, remove the nth node from the end of list and return its head.

For example,

```   Given linked list: 1->2->3->4->5, and n = 2.

After removing the second node from the end, the linked list becomes 1->2->3->5.
```

Note:
Given n will always be valid.
Try to do this in one pass.

Analysis:

The key to solve this problem is to use two pointers: pre and cur. The pre pointer moves N steps in the first place,

• ### Leetcode – LRU cache solution in Java

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.

get(key) – Get the value (will always be positive) of the key if the key exists in the cache, otherwise return -1.
set(key, value) – Set or insert the value if the key is not already present. When the cache reached its capacity, it should invalidate the least recently used item before inserting a new item.

Analysis

The popular method to implement an LRU cache is to use a bounded Queue.

The key to for implementing an LRU is to put any recently used data at the head of the queue.

• ### Learn Python List by Examples

Python List is a powerful data structure that you almost need it in every program. Python List can be used to hold a collection of items which can  be any type. In this post, I will use examples to describe how to use python List.

Python List Declaration

It is easy to create a python list object. The following code declare a List L and initialize it with 4 values.

In [1]:

```L = [1, 2, 'Jim', ('hello, word')]
print L
```

```[1, 2, 'Jim', 'hello, word']
```

Data look up in python List

We can locate the elements in the List by index.