EKG sequence convergence: Difference between revisions
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EKGs of [5, 7] converge at term 21
EKGs of [2, 5, 7, 9, 10] converge at term 45
</pre>
=={{header|Vlang}==
{{trans|Go}}
<lang vlang>fn gcd(aa int, bb int) int {
mut a,mut b:=aa,bb
for a != b {
if a > b {
a -= b
} else {
b -= a
}
}
return a
}
fn are_same(ss []int, tt []int) bool {
mut s,mut t:=ss.clone(),tt.clone()
le := s.len
if le != t.len {
return false
}
s.sort()
t.sort()
for i in 0..le {
if s[i] != t[i] {
return false
}
}
return true
}
const limit = 100
fn main() {
starts := [2, 5, 7, 9, 10]
mut ekg := [5][limit]int{}
for s, start in starts {
ekg[s][0] = 1
ekg[s][1] = start
for n in 2..limit {
for i := 2; ; i++ {
// a potential sequence member cannot already have been used
// and must have a factor in common with previous member
if !ekg[s][..n].contains(i) && gcd(ekg[s][n-1], i) > 1 {
ekg[s][n] = i
break
}
}
}
println("EKG(${start:2}): ${ekg[s][..30]}")
}
// now compare EKG5 and EKG7 for convergence
for i in 2..limit {
if ekg[1][i] == ekg[2][i] && are_same(ekg[1][..i], ekg[2][..i]) {
println("\nEKG(5) and EKG(7) converge at term ${i+1}")
return
}
}
println("\nEKG5(5) and EKG(7) do not converge within $limit terms")
}</lang>
{{out}}
<pre>
EKG( 2): [1, 2, 4, 6, 3, 9, 12, 8, 10, 5, 15, 18, 14, 7, 21, 24, 16, 20, 22, 11, 33, 27, 30, 25, 35, 28, 26, 13, 39, 36]
EKG( 5): [1, 5, 10, 2, 4, 6, 3, 9, 12, 8, 14, 7, 21, 15, 18, 16, 20, 22, 11, 33, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32]
EKG( 7): [1, 7, 14, 2, 4, 6, 3, 9, 12, 8, 10, 5, 15, 18, 16, 20, 22, 11, 33, 21, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32]
EKG( 9): [1, 9, 3, 6, 2, 4, 8, 10, 5, 15, 12, 14, 7, 21, 18, 16, 20, 22, 11, 33, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32]
EKG(10): [1, 10, 2, 4, 6, 3, 9, 12, 8, 14, 7, 21, 15, 5, 20, 16, 18, 22, 11, 33, 24, 26, 13, 39, 27, 30, 25, 35, 28, 32]
EKG(5) and EKG(7) converge at term 21
</pre>
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