initial commit

Author: ddlees

README.md

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+# Staff Services Software Engineer Coding Exercise
+
+## The Sieve of Eratosthenes
+
+Prime numbers have many modern day applications and a long history in mathematics. Utilizing your own resources research the sieve of Eratosthenes, an algorithm for generating prime numbers. Based on your research, implement an API in `pkg/sieve/sieve.go` that allows the caller to retrieve the Nth prime number.
+Some stub code and a test suite have been provided as a convenience, however, you are encouraged to deviate from Eratosthenes's algorithm, modify the existing functions/methods or anything else that might showcase your ability provided the following requirements are satisfied. 
+
+### Requirements
+
+- A url to a publically accessible `git` repository (GitHub, GitLab, self-hosted, etc) of the completed exercise must be given to your coordinator at least 24 hours in advance of the technical interview
+- Interviewers must be able to clone the repository via `git clone` 
+- Interviewers must be able to execute a suite of tests via `go test ./...`
+- The go library package provides an API for retrieving the Nth prime number using 0-based indexing where the 0th prime number is 2
+
+### Considerations
+
+During the technical interview, your submission will be discussed and you will be evaluated in the following areas:
+
+- Technical ability
+- Communication skills
+- Work habits and complementary skills

go.mod

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+module ssse-exercise-sieve
+
+go 1.19
+
+require github.com/stretchr/testify v1.8.1
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,17 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

pkg/sieve/sieve.go

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+package sieve
+
+type Sieve interface {
+	NthPrime(n int64) int64
+}
+
+func NewSieve() Sieve {
+	panic("unimplemented")
+}

pkg/sieve/sieve_test.go

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+package sieve
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNthPrime(t *testing.T) {
+	sieve := NewSieve()
+
+	assert.Equal(t, 2, sieve.NthPrime(0))
+	assert.Equal(t, 71, sieve.NthPrime(19))
+	assert.Equal(t, 541, sieve.NthPrime(99))
+	assert.Equal(t, 3581, sieve.NthPrime(500))
+	assert.Equal(t, 7793, sieve.NthPrime(986))
+	assert.Equal(t, 17393, sieve.NthPrime(2000))
+	assert.Equal(t, 15485867, sieve.NthPrime(1000000))
+}
+
+func FuzzNthPrime(f *testing.F) {
+	sieve := NewSieve()
+
+	f.Fuzz(func(t *testing.T, n int64) {
+		if !big.NewInt(sieve.NthPrime(n)).ProbablyPrime(0) {
+			t.Errorf("the sieve produced a non-prime number at index %d", n)
+		}
+	})
+}