Understanding these data structures and how they work is important for being able to write efficient code during coding interviews. Moreover, being able to choose the appropriate data structure for a particular problem can often be the difference between solving the problem easily and struggling to solve it at all.
Arrays and Linked Lists are two important data structures in computer science. Both are used to store and access collections of data. While arrays are used to store a collection of items in a linear fashion, linked lists are used to store items in a non-continuous way.
Both Arrays and Linked Lists have their advantages and disadvantages, and choosing between the two depends on the specific use case. However, having a good understanding of both data structures is essential for coding interviews and for writing efficient and effective code.
A stack is a data structure that follows the Last-In-First-Out (LIFO) principle. It means the element that is inserted last is the first one to come out. The operations performed on the stack are Push and Pop. We use the Push operation to insert an element into a stack, and the Pop operation to remove an element from it. The top element of the stack is the one that you can access for reading, writing, or deleting.
A queue is a data structure that follows the First-In-First-Out (FIFO) principle. It means the element that is inserted first will come out first. The operations performed on the queue are Enqueue and Dequeue. The Enqueue operation inserts an element in the queue, and Dequeue operation removes elements from the queue. The front element of the queue is the one that you can access for reading, writing, or deleting.
A tree is a hierarchical data structure that consists of nodes connected by edges. The topmost node is called the root, and each node can have zero or more children nodes. Trees are commonly used to represent various hierarchical structures, such as computer file systems, organization charts, and family trees.
A graph is a non-linear data structure that consists of nodes and edges. Unlike trees, graphs can have cycles and can be used to represent various complex structures, such as social networks, transportation networks, and computer networks.
Map: A Map is a collection of key-value pairs where each value can be accessed using its associated key. It allows any type of value to be used as a key and provides efficient methods for adding, getting, deleting, and checking the presence of key-value pairs. Maps maintain the order of insertion of key-value pairs and their size can be retrieved using the ‘size’ property.
Set: A Set is a collection of unique values where each value can only be added once and any duplicate values are automatically ignored. It provides efficient methods for adding, deleting, and checking the presence of elements. Sets maintain the order of insertion of elements and their size can be retrieved using the ‘size’ property.
Both Maps and Sets are useful for solving various problems in coding interviews, such as finding duplicates in an array, counting the frequency of elements, and efficiently storing data.
Another popular algorithm for sorting arrays is the bubble sort algorithm. It works by comparing each element in the array with its adjacent element and swapping them if they are not in the desired order. The bubble sort algorithm is simple to implement, but it is not very efficient for sorting large arrays.
The indexof() function returns the index of the first occurrence of a specified value in an array. The includes() function returns a Boolean value indicating whether a specified value is in an array. The find() function returns the first element in an array that satisfies a specified condition.
- Understand the time complexities: Know the time and space complexities for each data structure and its operations. This knowledge will help you write efficient code during your interviews.
- Solve problems: Practice solving coding problems that involve data structures. This will help you apply your knowledge and give you more confidence during your interview.
- Ask for feedback: Get feedback from others on your code and solutions. This will help you find areas where you can improve and learn from others.