I. The Importance of Data Structures and Algorithms
1.1 Definition of Data Structure and Algorithm
Data structures, as the name suggests, are structures used to store and organize data. They can be used to implement efficient data access and manipulation. Common data structures include arrays, linked lists, stacks, queues, hash tables, trees, and graphs.
An algorithm is a series of operational steps specified in order to solve a specific problem. It can be used to perform operations on data structures such as sorting, searching, inserting and deleting etc.
1.2 Why do we need data structures and algorithms
Data structures and algorithms are the cornerstones of programming. Choosing the right data structures and algorithms can greatly improve the efficiency of a program. For example, for scenarios where elements need to be looked up frequently, using a hash table may be more efficient than using an array. For scenarios that require frequent insertion and deletion operations, a linked list may be a better choice.
In addition, many problems are essentially data structure and algorithm problems. For example, the network routing problem can be regarded as the problem of finding the shortest path in the graph, and this requires the use of relevant knowledge of the graph and search algorithms.
II. Basic Data Structure
2.1 Arrays
An array is a basic data structure that stores data of the same type contiguously in memory. The main advantage of arrays is the fast access to elements through indexing. However, the size of the array is fixed and elements cannot be added or removed dynamically.
2.2 Linked list
A linked list is made up of nodes, each node contains data and a reference to the next node. The advantage of the linked list is that nodes can be inserted or deleted at any position, but accessing elements in the linked list requires traversal from the head node.
2.3 Stacks and Queues
The stack is a last-in-first-out (LIFO) data structure that only allows insertion and deletion at the top of the stack. A queue is a first-in-first-out (FIFO) data structure that allows elements to be inserted at the end of the queue and elements to be deleted at the head.