Recently I started grinding their basics, including java related data structures. Also lay the foundation for later examination. Today is an overview of some of the data structure, mainly on human knowledge summary facilitate their subsequent review. First statement about herein, this and subsequent blog content will be taken from the "Westward design mode" or books or blog, see if there are duplicate content, please do not spray me. In line with a principle: To summarize learning knowledge to facilitate their
access to, if we can be helpful to others, deeply honored!
1. The basic concepts and terminology
Before learning, to understand the basic concepts. Data structure divided into two parts can be appreciated, a data, a structure.
1.1 Data
Data descriptor refers objective things, the object is operable in a computer, the computer set of symbols can be identified and processed. And other such numerical integer type, and further comprising a number of characters and non-numeric type of sound, images and video.
Data is actually a symbol, but to have two premises
- It may be input to the computer.
- The computer program can be processed.
1.2 Data Elements
Data is an integral element of data, there is a sense of basic units. It is the basic unit of data.
1.3 Data entry
Generally, a data element may consist of a number of data items. Data items may also be called fields, fields, properties and the like.
Item is the smallest indivisible unit.
1.4 Data Objects
Data object is a collection of data elements of the same nature, it is a subset of the data.
1.5 Data Structure
Configuration, that is simple to understand that relationship, such as the molecular structure, that is composed of arrangement between the atoms of the molecules. Strictly speaking, the structure refers to the various components with each other and aligned manner. In real life, between different data elements are not independent, but there is a specific relationship, these relationships will be called structures.
Then, the data structure is the presence of a collection of one or more data elements of a particular relationship to each other.
2. Logical Structure and Physical Structure
According to a different viewpoint, the data structure can be divided into logical and physical structure.
2.1 Logical Structure
Logical structure refers to the relationship between the data elements in the data objects. Into four logical structure, as shown below:
- A structured collection
of data elements in addition to the set of structures belong to the same set, no other relations between them. Equality between the various elements of common property is part of the same collection. - Linear structure
linear structure is one to one relationship between data elements. As shown in FIG. - Tree
tree hierarchy that exists between the relationship of one to many data elements. As shown in FIG. - Graph structure
data elements graphic structure is many to many relationship. As shown in FIG.
When the logical structure data represents a schematic Precautions:
- Each data element considered as a node, represented by circles.
- The logical relationship between the elements indicated by the connection between nodes, if there is a relationship between the direction, indicated by the arrowed connections.
2.2 Physical Structure (storage structure)
It refers to a physical structure in the form of logical structure data stored in the computer. Data collection of data elements, by definition, is how actual data elements stored in the memory of the computer. The memory is for the memory in terms of external data memory as a hard disk, floppy disk, optical disk, etc. usually described by the file structure.
Storage structure of two data structures: sequential storage and chain stores.
Sequential storage structure
sequential storage element data structure is stored in the memory cells in consecutive addresses, and the logical relationships between the physical relationship which is consistent with the data. As shown below:
Storage Structure
Storage Structure data element is stored in an arbitrary storage unit, the group of memory cells which may be continuous, may be discontinuous. As shown below:
3. Abstract Data Types
- Data type
Data type refers to the same set of properties and defining a value of some general term operation on this collection. - Abstract data model
abstract data model (Abstract Data Type, ADT) refers to a mathematical model and a set of operations defined in the model.
summary
这是整理书上的一些基本概念，做个笔记。在看其他人的博客的时候，也看到了一些熟悉的内容，相信很多人看过这本书，也做了记录。别人的学习记录是别人的，自己学习要整理自己的……