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ythosa/main.go

Created February 17, 2021 18:22
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  1. ythosa created this gist Feb 17, 2021.
    92 changes: 92 additions & 0 deletions main.go
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,92 @@
    package main

    import "fmt"

    type eratosthenesSieve struct {
    sieve []bool
    maxN int
    }

    func newEratosthenesSieve(maxN int) *eratosthenesSieve {
    var sieve eratosthenesSieve

    sieve.sieve = append(sieve.sieve, false)
    sieve.sieve = append(sieve.sieve, false)
    for i := 2; i < maxN; i++ {
    sieve.sieve = append(sieve.sieve, true)
    }

    sieve.maxN = maxN

    return &sieve
    }

    func (s *eratosthenesSieve) fill() {
    for i := 2; i*i < s.maxN; i++ {
    if s.sieve[i] {
    for j := i * i; j < s.maxN; j += i {
    s.sieve[j] = false
    }
    }
    }
    }

    func (s *eratosthenesSieve) String() string {
    result := ""

    for i, isPrime := range s.sieve {
    if isPrime {
    result += fmt.Sprintf("%d ", i)
    }
    }

    return result
    }

    type sophieGermainNumbers struct {
    primeNumbers []bool
    filtered []int
    }

    func newSofiZhemenNumbers(primeNumbers []bool) *sophieGermainNumbers {
    var model sophieGermainNumbers

    model.primeNumbers = primeNumbers

    return &model
    }

    func (s *sophieGermainNumbers) filterPrimeNumbers() {
    for i := 2; i < len(s.primeNumbers); i++ {
    nextPos := 2*i + 1
    if nextPos >= len(s.primeNumbers) {
    return
    }

    if s.primeNumbers[i] && s.primeNumbers[nextPos] {
    s.filtered = append(s.filtered, i)
    }
    }
    }

    func (s *sophieGermainNumbers) String() string {
    result := ""

    for _, n := range s.filtered {
    result += fmt.Sprintf("%d ", n)
    }

    return result
    }

    func main() {
    const maxNumber = 10000

    erSieve := newEratosthenesSieve(maxNumber)
    erSieve.fill()

    sofiZhemenNums := newSofiZhemenNumbers(erSieve.sieve)
    sofiZhemenNums.filterPrimeNumbers()

    fmt.Println(sofiZhemenNums)
    }