Greatest Common Divisor

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Revision as of 11:56, 10 October 2022 by Admin (talk | contribs) (Created page with "== Problem Description== The greatest common divisor, sometimes also called the highest common divisor (Hardy and Wright 1979, p. 20), of two positive integers a and b is the largest divisor common to a and b. For example, GCD(3,5)=1, GCD(12,60)=12, and GCD(12,90)=6. The greatest common divisor GCD(a,b,c,...) can also be defined for three or more positive integers as the largest divisor shared by all of them. Two or more positive integers that have greatest common divis...")
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Problem Description

The greatest common divisor, sometimes also called the highest common divisor (Hardy and Wright 1979, p. 20), of two positive integers a and b is the largest divisor common to a and b. For example, GCD(3,5)=1, GCD(12,60)=12, and GCD(12,90)=6. The greatest common divisor GCD(a,b,c,...) can also be defined for three or more positive integers as the largest divisor shared by all of them. Two or more positive integers that have greatest common divisor 1 are said to be relatively prime to one another, often simply just referred to as being "relatively prime."

Bounds Chart

Greatest Common DivisorBoundsChart.png

Step Chart

Greatest Common DivisorStepChart.png

Improvement Table

Complexity Classes Algorithm Paper Links Lower Bounds Paper Links
Exp/Factorial
Polynomial > 3
Cubic
Quadratic [ Euclid's algorithm (-300)]

[ Lehmer's GCD algorithm (1940)]

[ Binary GCD algorithm (1967)]

Sthele, Zimmermann (2006)

nlogn
Linear
logn