Data structure and algorithmic terminology learning notes

Data structure : is a collection of elements of one or more specific relationships that exist between each other.

Data : is the symbol that describes the objective things, is the computer can manipulate the object, is can be recognized by the computer, and input to the computer processing symbol set. Data includes not only integer type, real type and other numeric types, but also non-numeric types such as character and sound, image, video, etc.

Data elements: is a basic unit of meaning that makes up data and is usually treated as a whole in a computer. is also a record.

data item: A data element can consist of several data items. A data item is the smallest unit of data that is inseparable.

data object: is a collection of data elements of the same nature, and is a subset of the data.

According to the different viewpoints, we have the structure of data structure into logical and physical structure:

Logical Structure: refers to the interrelationship between data elements in a data object. The logical structure is divided into the following four types:

1. Collection structure: The data elements in the collection structure are not related to each other except for the same set;

2, linear structure: The data element in the linear structure is a one-on relationship;

3. Tree structure: There is a one-to-many hierarchical relationship between the data elements in the tree structure;

4. Graphic structure: data elements of graphic structure are many-to-many relationships

Physical Structure: refers to the logical structure of data and the storage form in the computer. There are two ways to store data elements: sequential storage and chained storage

1, sequential storage structure: is the data element stored in the address continuous storage unit, its data between the logical relationship and physical relationship is consistent;

2, chain storage structure: is the data elements stored in any storage unit, this group of storage units can be continuous, or can be discontinuous.

algorithm: An algorithm is a description of the solution steps for a particular problem, represented as a finite sequence of instructions in a computer, and each instruction represents one or more operations.

features of the algorithm: input, output, poor, deterministic and feasible

1, input and output: The algorithm has at least 0 or more inputs, at least one or more outputs

2, Poor: Refers to the algorithm after the implementation of a limited number of steps, automatically end without an infinite loop, and each step in an acceptable time to complete;

3, certainty: Each step of the algorithm has a definite meaning, will not appear two semantics;

4, Feasibility: Every step of the algorithm must be feasible, that is, each step can be done through a finite number of times.

Requirements for algorithmic design:

1, correctness: The correctness of the algorithm is that the algorithm should have at least input, output and processing without ambiguity, can correctly reflect the needs of the problem, can get the correct answer to the problem;

2, readability: Another purpose of the algorithm design is to facilitate reading, understanding and communication;

3, Robustness: When the input data is not valid, the algorithm can also make relevant processing, rather than produce abnormal or inexplicable results;

4, the design algorithm should try to meet the time efficiency and low storage capacity requirements.

Data structure and algorithmic terminology learning notes