Introduction

There are a variety of algorithms that we rely on as software engineers on a daily basis. Below is a list of the most commonly used ones. These have mostly been taken from the wikipedia list of algorithms and augmented where neccessary. These are algorithms I have run into or relied on in the past 10 years. If I have never run into it, it didn't make the list.

List of Common Algorithms

ComparisonOfAlgorithms

General combinatorial algorithms

• Floyd's cycle-finding algorithm: finds cycles in iterations
• Mersenne twister: PRNG

Graph algorithms

• Floyd-Warshall algorithm: solves the all pairs shortest path problem in a weighted, directed graph
• Topological sort: finds linear order of nodes based on their dependencies
• Coloring algorithm: Graph coloring algorithm
• Kruskal's algorithm: find a minimum spanning tree for a graph

Search algorithms

• Linear search: finds an item in an unsorted list
• Binary search: locates an item in a sorted list
• Breadth-first search: traverses a graph by level
• Depth-first search: traverses a graph branch by branch
• Hash table: finds an item in an unsorted collection in O(1) time.

String algorithms

Searching

• Boyer-Moore string search algorithm: amortised linear algorithm
• Knuth-Morris-Pratt algorithm: bypasses reexamination of matched characters

Approximate matching

• Levenshtein edit distance
• Metaphone: an algorithm for indexing words by their sound, when pronounced in english
• Soundex

Sorting algorithms

• Bubble sort: for each pair if indices, swap the items if out of order
• Heapsort: convert the list into a heap, keep removing the largest element from the heap and adding it to the end of the list
• Insertion sort: determine where the current item belongs in the list of sorted ones and insert it there.
• Merge sort: sort the first and second half of the lists separately, then merge the sorted lists
• Quicksort: divide list into two, with all items on the first list coming before all items on the second list; then sort the two lists.
• Selection sort: pick the smallest of the remaining elements.

Compression algorithms

Lossless compression algorithms

• Huffman coding

Computational geometry

• Convex hull algorithms
• Gift wrapping algorithm

Cryptographic algorithms

• Symmetric (secret key) encryption
• Asymmetric (public key) encryption
• Cryptographic message digest functions (hashing functions)

Digital signal processing

• Discrete Fourier transform
• Fast Fourier transform

Software engineering

• Cyclick redundancy check: calculation of a check word
• Parity: simple/fast error detection technique

Distributed systems algorithms

• Lamport ordering: a partial ordering of events based on the happened-before relation
• Byzantine fault tolerance: good fault tolerance

Memory allocation and deallocation algorithms

• Mark and sweep

Operation systems algorithms

• Banker's algorithm: algorithm used for deadlock avoidance.

Process synchronisation

• Lamport's bakery algorithm

Scheduling

• Round-robin scheduling
• Fair-share scheduling

Machine learning algorithms

• Support vector machines

Neural networks

• Backpropagation
• Self-organizing map

Number theoretic algorithms

• Euclidean algorithm: generates the greatest common divisor

Numerical algorithms

• Newton's method

Optimizing algorithms

• Particle swarm
• Random-restart hill climbing
• Local search

Parsing

• Recursive decent parser: a top-down parser suitable for LL(k) grammars
• LL parser: a simple linear time parsing algorithm for a limited class of context-free grammars
• LR parser: A more complex linear time parsing algorithm for a larger class of context-free grammars.

Other

• Xor swap algorithm: swaps the values of two variables without using a buffer
• Stemming algorithm: a method of reducing words to their stem, base, or root form
• Hamming weight (population count): find the number of 1 bits in a binary word