Super-d numbers: Difference between revisions

Content added Content deleted
(Added Fōrmulæ)
(→‎{{header|Go}}: Simplified somewhat, about 10% quicker than before.)
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=={{header|Go}}==
=={{header|Go}}==
Simple brute force approach and so not particularly quick - about 2.5 minutes on a Core i7.
Simple brute force approach and so not particularly quick - about 2.25 minutes on a Core i7.
<lang go>package main
<lang go>package main


Line 79: Line 79:
"time"
"time"
)
)

func pow(n uint64, exp int) *big.Int {
b := new(big.Int).SetUint64(n)
⚫
p := new(big.Int).Set(b)
⚫
for i := 2; i <= exp; i++ {
p.Mul(p, b)
}
return p
}


func main() {
func main() {
start := time.Now()
start := time.Now()
rd := []string{"22", "333", "4444", "55555", "666666", "7777777", "88888888", "999999999"}
rd := []string{"22", "333", "4444", "55555", "666666", "7777777", "88888888", "999999999"}
for i := 2; i <= 9; i++ {
one := big.NewInt(1)
⚫
nine := big.NewInt(9)
⚫
for i := big.NewInt(2); i.Cmp(nine) <= 0; i.Add(i, one) {
fmt.Printf("First 10 super-%d numbers:\n", i)
fmt.Printf("First 10 super-%d numbers:\n", i)
bigi := big.NewInt(int64(i))
ii := i.Uint64()
k := new(big.Int)
k := new(big.Int)
count := 0
count := 0
inner:
inner:
for j := uint64(3); ; j++ {
for j := big.NewInt(3); ; j.Add(j, one) {
k.Mul(bigi, pow(j, i))
k.Exp(j, i, nil)
ix := strings.Index(k.String(), rd[i-2])
k.Mul(i, k)
ix := strings.Index(k.String(), rd[ii-2])
if ix >= 0 {
if ix >= 0 {
count++
count++
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First 10 super-3 numbers:
First 10 super-3 numbers:
261 462 471 481 558 753 1036 1046 1471 1645
261 462 471 481 558 753 1036 1046 1471 1645
found in 0 ms
found in 1 ms


First 10 super-4 numbers:
First 10 super-4 numbers:
1168 4972 7423 7752 8431 10267 11317 11487 11549 11680
1168 4972 7423 7752 8431 10267 11317 11487 11549 11680
found in 5 ms
found in 7 ms


First 10 super-5 numbers:
First 10 super-5 numbers:
4602 5517 7539 12955 14555 20137 20379 26629 32767 35689
4602 5517 7539 12955 14555 20137 20379 26629 32767 35689
found in 23 ms
found in 28 ms


First 10 super-6 numbers:
First 10 super-6 numbers:
27257 272570 302693 323576 364509 502785 513675 537771 676657 678146
27257 272570 302693 323576 364509 502785 513675 537771 676657 678146
found in 350 ms
found in 285 ms


First 10 super-7 numbers:
First 10 super-7 numbers:
140997 490996 1184321 1259609 1409970 1783166 1886654 1977538 2457756 2714763
140997 490996 1184321 1259609 1409970 1783166 1886654 1977538 2457756 2714763
found in 1768 ms
found in 1517 ms


First 10 super-8 numbers:
First 10 super-8 numbers:
185423 641519 1551728 1854230 6415190 12043464 12147605 15517280 16561735 18542300
185423 641519 1551728 1854230 6415190 12043464 12147605 15517280 16561735 18542300
found in 12912 ms
found in 11117 ms


First 10 super-9 numbers:
First 10 super-9 numbers:
17546133 32613656 93568867 107225764 109255734 113315082 121251742 175461330 180917907 182557181
17546133 32613656 93568867 107225764 109255734 113315082 121251742 175461330 180917907 182557181
found in 151070 ms
found in 135616 ms
</pre>
</pre>


Retrieved from "https://rosettacode.org/wiki/Super-d_numbers"