Elaine M. McGraw (née Boehme) was an American computer programmer who, together with

Arthur Samuel Arthur Lee Samuel (December 5, 1901 – July 29, 1990) was an American pioneer in the field of computer gaming and artificial intelligence. He popularized the term "machine learning" in 1959. The Samuel Checkers-playing Program was among the wo ...

and

Gene Amdahl Gene Myron Amdahl (November 16, 1922 – November 10, 2015) was an American computer architect and high-tech entrepreneur, chiefly known for his work on mainframe computers at IBM and later his own companies, especially Amdahl Corporation ...

, invented

open addressing Open addressing, or closed hashing, is a method of collision resolution in hash tables. With this method a hash collision is resolved by probing, or searching through alternative locations in the array (the ''probe sequence'') until either the t ...

based

hash table In computing, a hash table, also known as hash map, is a data structure that implements an associative array or dictionary. It is an abstract data type that maps keys to values. A hash table uses a hash function to compute an ''index'', ...

s in 1954. After studying economics, McGraw began working as a computer programmer for The Prudential Life Insurance Company in the early 1950s, using a

UNIVAC UNIVAC (Universal Automatic Computer) was a line of electronic digital stored-program computers starting with the products of the Eckert–Mauchly Computer Corporation. Later the name was applied to a division of the Remington Rand company an ...

computer. Prudential sent her to IBM to learn how to program the IBM 701, but (believing that Prudential would not purchase this computer) she applied for a job at IBM, and was hired there in 1953 by

. She continued to work at IBM until at least 1970.. In 1954, McGraw was working with Amdahl and

on an

assembler Assembler may refer to: Arts and media * Nobukazu Takemura, avant-garde electronic musician, stage name Assembler * Assemblers, a fictional race in the ''Star Wars'' universe * Assemblers, an alternative name of the superhero group Champions of ...

(a program for converting a textual description of a sequence of computer instructions into

machine code In computer programming, machine code is any low-level programming language, consisting of machine language instructions, which are used to control a computer's central processing unit (CPU). Each instruction causes the CPU to perform a ve ...

) and she was tasked with implementing a

symbol table In computer science, a symbol table is a data structure used by a language translator such as a compiler or interpreter, where each identifier (or symbols), constants, procedures and functions in a program's source code is associated with info ...

for it. Together, Amdahl, McGraw, and Samuel solved this problem by inventing the methods of

and

linear probing Linear probing is a scheme in computer programming for resolving collisions in hash tables, data structures for maintaining a collection of key–value pairs and looking up the value associated with a given key. It was invented in 1954 by Gene ...

, still frequently used in modern

data structures. This was not the first use of hash tables – hash tables with chaining had already been described in a 1953 memo by

Hans Peter Luhn Hans Peter Luhn (July 1, 1896 – August 19, 1964) was a German researcher in the field of computer science and Library & Information Science for IBM, and creator of the Luhn algorithm, KWIC (Key Words In Context) indexing, and Selective ...

– but was nevertheless an influential early contribution to the theory of data structures.

References

American computer scientists American women computer scientists Possibly living people Year of birth missing {{US-compu-bio-stub