## Bezout Identity Calculator

## Answers to Questions

### What is Bezout Identity?

The Bachet-**Bezout identity** is defined as : if \( a \) and \( b \) are two integers and \( d \) is their GCD, then it exists \( u \) and \( v \), two integers such as \( au + bv = d \).

Example: \( a=12 \) and \( b=30 \), gcd \( (12, 30) = 6 \). There are multiple solutions to \( u \) and \( v \) such as \( 12u + 30v = 6 \), such as : $$ 12 \times -2 + 30 \times 1 = 6 $$

The dCode **Bezout coefficients** calculator gives only one solution.

### What are Bezout coefficients?

The **Bézouts coefficients** are the values \( u \) and \( v \).

### How to calculate values for Bézout Identity?

The dCode program uses the gcd">extended GCD algorithm. \( a \) and \( b \) are two non-zero positive integers.

The algorithm of dCode consists of a sequence of Euclidean divisions for finding the **Bezout coefficients** (and also the GCD).

### How to code Bézout Identity in pseudo-code?

A source code for the **identity of Bezout** would be similar to this pseudo-code:

`Initialization r = a, r' = b, u = 1, v = 0, u' = 0 and v' = 1`

While (r' != 0)

q = (int) r/r'

rs = r, us = u, vs = v,

r = r', u = u', v = v',

r' = rs - q*r', u' = us - q*u', v' = vs - q*v'

End While

Return (r, u, v)

## Source code

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