From m-w.com: an algorithm is: broadly, a step-by-step procedure for solving a problem or accomplishing some end especially by a computer
The theory of algorithms deals with the study of characteristics of algorithms such as efficiency in terms of time and space.
Data Structures
Hash Table
Graph
Union Find
Sorting and Searching
Sorting is O(n log n)
Order statistics
Card shuffling algorithms
String Searching
Parsing and formal languages
Graph Theory
Computational Geometry
Numerical algorithms
P and NP
Cook's theorem
P = NP, P=NP?
Heuristic Algorithms
People
Bibliography