POSTS

Are you preparing to give coding interviews? Then having the knowledge of the most used and prominent algorithms becomes a must.

An algorithm is a set of instructions used to solve complex real-life problems in seconds. One algorithm can solve many problems; all you need is to brainstorm to know which algorithm will correctly and efficiently solve your problem.

There are many problems, so their corresponding solutions, i.e., algorithms. However, you need not memorize all of them, all you need is an understanding of fundamentals, and there is no question you will leave unanswered in a coding interview.

Here are the top 10 algorithms for the coding interview that you should know as a developer.

1. Linear Search

Also known as a sequential search algorithm, linear search is extensively used to search for an element from an unstructured list. In Linear search, we simply pass over the whole list and match each part of the list with the item whose position we want to find. If the match is found, then the item's position is returned; otherwise, the algorithm returns null.

2. Binary Search

While searching for an element, linear search passes through the entire list, starting from the first item, but the binary search algorithm starts with the middle item. If the matched item is found, then the position of the central item is returned. Otherwise, we search into either of the halves depending on the result produced through the match. Since binary search is an interval search algorithm, it can be used only on well-structured lists.

3. Dynamic Programming

In Dynamic programming, each problem is divided into sub-problems, and the solution for the whole problem is dependent on the solution of these sub-problems. This is known as the principle of recursion. Here, the solution to subproblems is saved for future purposes, such as simplifying complex problems and reducing computation time.

4. Tree Traversal Algorithm

Trees are a unique form of data structure that includes a root node connected to sub-trees in a linked node format. Tree traversal is visiting each tree node while performing functions on all values. It is hierarchical, where the root node is connected via edges. There are many types of tree traversal possible, but these are common ones.

* Preorder traversal - Root-Left-Right

* In order traversal - Left-Right-Root

* Postorder traversal - Left-Root-Right

5. Graph Traversal Algorithm

A graph is a unique data structure in programming that comprises defined sets of nodes and edges. Its connected vertices and edges share defined connections or relationships. Graphs generally designate networks and help in solving complex problems.

There are two types of graph algorithms-

* Breadth-First - search starts at a specific vertex, and the algorithm tries to visit all the adjacent items before moving on to the next level of vertices.

* Depth-First - search starts from a specific vertex and explores as much as possible along with all the branches before backtracking.

6.  Bubble Sort

Bubble sort works by repeatedly interchanging neighboring elements until they are in the calculated order. 

Bubble sort is mainly used where -

* complexity does not matter

* simple and shortcode are preferred

7.  Insertion Sort

 Unlike bubble sort, where the program starts with the first item, insertion sorts the adjacent items, reaches the last item, and then starts at the first item again to repeatedly go through this operation and sort the whole array. In simple words, it starts with the first item and, as it moves towards the last item, sorts all the items that it passes.

8. Selection Sort

 Selection Sort performs its operation by finding the smallest or largest items and placing them first. It then leaves out the first item, repeats the process with the leftover array, and sets the next smallest or most prominent element in the second position. This operation continues until all elements in the array have been sorted into their demanded positions.

9. Merge Sort

It is the practice of splitting the problem into smaller pieces, solving them each by one, and then merging them. It divides the list in half and applies the sort function to the two halves. Those two halves are then sorted and combined using the merge function.

10. Hashing Insertion

A hashing insertion is a coded hash function. It is an algorithm that charts data of arbitrary size to a specific or fixed-length hash. It converts complex input into compressed values.

The hash function generates a hash value built on the input data blocks with specific-length data. However, a hashing algorithm explains how the hash function will be used and defines the complete operation of breaking up the message and bringing it back together.

Three most common hash algorithms

* Secure Hash Algorithm

* Whirlpool

* Message digest (MD5)

It can be hard to recall these algorithms during an interview. So, revise repeatedly and use these algorithms to solve different problems to boost your confidence.