Jordan-Pólya numbers: Difference between revisions
→{{header|Wren}}: Added a second much faster version.
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=={{header|Wren}}==
===Version 1===
{{libheader|Wren-set}}
{{libheader|Wren-seq}}
Line 506 ⟶ 507:
The 3,800th Jordan-Pólya number is : 7,213,895,789,838,336
= (4!)⁸ x (2!)¹⁶
</pre>
===Version2===
{{libheader|Wren-sort}}
This uses the same non-recursive algorithm as the Phix entry to generate the J-P numbers which, at 1.1 seconds on my machine, is about 40 times quicker than the OEIS algorithm.
<syntaxhighlight lang="ecmascript">import "./sort" for Find
import "./seq" for Lst
import "./fmt" for Fmt
var factorials = List.filled(19, 1)
var cacheFactorials = Fn.new {
var fact = 1
for (i in 2..18) {
fact = fact * i
factorials[i] = fact
}
}
var JordanPolya = Fn.new { |limit|
var ix = Find.nearest(factorials, limit).min(18)
var res = factorials[0..ix]
var k = 2
while (k < res.count) {
var rk = res[k]
for (l in 2...res.count) {
var kl = res[l] * rk
if (kl > limit) break
while (true) {
var p = Find.nearest(res, kl)
if (p < res.count && res[p] != kl) {
res.insert(p, kl)
} else if (p == res.count) {
res.add(kl)
}
kl = kl * rk
if (kl > limit) break
}
}
k = k + 1
}
return res[1..-1]
}
var Decompose = Fn.new { |n, start|
if (!start) start = 18
if (start < 2) return []
var m = n
var f = []
for (i in start..2) {
while (m % factorials[i] == 0) {
f.add(i)
m = m / factorials[i]
if (m == 1) return f
}
}
return Decompose.call(n, start-1)
}
cacheFactorials.call()
var v = JordanPolya.call(2.pow(53)-1)
System.print("First 50 Jordan–Pólya numbers:")
Fmt.tprint("$4d ", v[0..49], 10)
System.write("\nThe largest Jordan–Pólya number before 100 million: ")
for (i in 1...v.count) {
if (v[i] > 1e8) {
Fmt.print("$,d\n", v[i-1])
break
}
}
for (i in [800, 1800, 2800, 3800]) {
Fmt.print("The $,r Jordan-Pólya number is : $,d", i, v[i-1])
var g = Lst.individuals(Decompose.call(v[i-1], null))
var s = g.map { |l|
if (l[1] == 1) return "%(l[0])!"
return Fmt.swrite("($d!)$S", l[0], l[1])
}.join(" x ")
Fmt.print("= $s\n", s)
}</syntaxhighlight>
{{out}}
<pre>
Identical to first version.
</pre>
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