Smarandache prime-digital sequence: Difference between revisions
Added Swift solution
(Added Wren) |
(Added Swift solution) |
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2,3,5,7,23,37,53,73,223,227,233,257,277,337,353,373,523,557,577,727,733,757,773,2237,2273
33223
</pre>
=={{header|Swift}}==
{{trans|C++}}
<lang swift>func isPrime(number: Int) -> Bool {
if number < 2 {
return false
}
if number % 2 == 0 {
return number == 2
}
if number % 3 == 0 {
return number == 3
}
if number % 5 == 0 {
return number == 5
}
var p = 7
let wheel = [4,2,4,2,4,6,2,6]
while true {
for w in wheel {
if p * p > number {
return true
}
if number % p == 0 {
return false
}
p += w
}
}
}
func nextPrimeDigitNumber(number: Int) -> Int {
if number == 0 {
return 2
}
switch number % 10 {
case 2:
return number + 1
case 3, 5:
return number + 2
default:
return 2 + nextPrimeDigitNumber(number: number/10) * 10
}
}
let limit = 1000000000
var n = 0
var max = 0
var count = 0
print("First 25 SPDS primes:")
while n < limit {
n = nextPrimeDigitNumber(number: n)
if !isPrime(number: n) {
continue
}
if count < 25 {
print(n, terminator: " ")
} else if count == 25 {
print()
}
count += 1
if (count == 100) {
print("Hundredth SPDS prime: \(n)")
} else if (count == 1000) {
print("Thousandth SPDS prime: \(n)")
} else if (count == 10000) {
print("Ten thousandth SPDS prime: \(n)")
}
max = n
}
print("Largest SPDS prime less than \(limit): \(max)")</lang>
{{out}}
<pre>
First 25 SPDS primes:
2 3 5 7 23 37 53 73 223 227 233 257 277 337 353 373 523 557 577 727 733 757 773 2237 2273
Hundredth SPDS prime: 33223
Thousandth SPDS prime: 3273527
Ten thousandth SPDS prime: 273322727
Largest SPDS prime less than 1000000000: 777777773
</pre>
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