package primes_test
import (
	"primes"
	"testing"
	"github.com/matryer/is"
)
var primeCases = []struct {
	input    int
	expected []int
}{
	{0, []int{}},
	{1, []int{}},
	{2, []int{2}},
	{10, []int{2, 3, 5, 7}},
	{100, []int{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}},
}
var sieveCases = []struct {
	input    int
	expected []bool
}{
	// every non-prime is true, 0-th and 1-st is false, should be true
	{0, []bool{false}},
	{1, []bool{false, false}},
	{2, []bool{false, false, false}},
	{100, []bool{false, false, false, false, true, false, true, false, true, true, true, false, true, false, true, true, true, false, true, false, true, true, true, false, true, true, true, true, true, false, true, false, true, true, true, true, true, false, true, true, true, false, true, false, true, true, true, false, true, true, true, true, true, false, true, true, true, true, true, false, true, false, true, true, true, true, true, false, true, true, true, false, true, false, true, true, true, true, true, false, true, true, true, false, true, true, true, true, true, false, true, true, true, true, true, true, true, false, true, true, true}},
}
	is := is.New(t)
	for _, tc := range sieveCases {
		is.Equal(tc.expected, primes.JustSieve(tc.input))
	}
}
	for i := 0; i < b.N; i++ {
		primes.JustSieve(1e6)
	}
}
	}
}
func BenchmarkConcurrentSieve(b *testing.B) {
	for i := 0; i < b.N; i++ {
		primes.ConcurrentSieve(1e6)
func BenchmarkJustSieve(b *testing.B) {
func TestConcSieve(t *testing.T) {
	is := is.New(t)
	for _, tc := range sieveCases {
		is.Equal(tc.expected, primes.ConcurrentSieve(tc.input))
	}
}
func TestJustSieve(t *testing.T) {
	{10, []bool{false, false, false, false, true, false, true, false, true, true, true}},

import (
	"sync"
)
const MAX = 105_000
func JustSieve(limit int) []bool {
	sieve := make([]bool, limit+1)
	for p := 2; p*p <= limit; p += 2 {
		if !sieve[p] {
			for i := p * p; i <= limit; i += p {
				sieve[i] = true
			}
			if p == 2 {
				p--
			}
		}
	}
	return sieve
}

func ConcurrentSieve(limit int) []bool {
	sieve := make([]bool, limit+1)
	wg := new(sync.WaitGroup)
	wg.Add(1)
	go func() {
		// handle even numbers
		for i := 2 * 2; i <= limit; i += 2 {
			sieve[i] = true
		}
		wg.Done()
	}()
	for p := 3; p*p <= limit; p += 2 {
		wg.Add(1)
		go func(p int) {
			if !sieve[p] {
				for i := p * p; i <= limit; i += p {
					sieve[i] = true
				}
			}
			wg.Done()
		}(p)
	}
	wg.Wait()
	return sieve
}

const MAX = 105_000