mirror/v
1
0
Fork 0
mirror of https://github.com/vlang/v.git synced 2023-08-10 21:13:21 +03:00
Code Issues Projects Releases Wiki Activity

math: add egcd function implementing the extended Euclidean algorithm (#11203)

Browse Source
This commit is contained in:
Miccah
2021-08-16 03:49:50 -05:00
committed by GitHub
parent 90b052b1db
commit d235de63e2
2 changed files with 28 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
vlib/math/math.v
View File

@ -89,6 +89,21 @@ pub fn gcd(a_ i64, b_ i64) i64 {
return a
}
// egcd returns (gcd(a, b), x, y) such that |a*x + b*y| = gcd(a, b)
pub fn egcd(a i64, b i64) (i64, i64, i64) {
mut old_r, mut r := a, b
mut old_s, mut s := i64(1), i64(0)
mut old_t, mut t := i64(0), i64(1)
for r != 0 {
quot := old_r / r
old_r, r = r, old_r % r
old_s, s = s, old_s - quot * s
old_t, t = t, old_t - quot * t
}
return if old_r < 0 { -old_r } else { old_r }, old_s, old_t
}
// lcm calculates least common (non-negative) multiple.
pub fn lcm(a i64, b i64) i64 {
if a == 0 {