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random.go
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random.go
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package main
import (
"errors"
"fmt"
"math/rand"
"time"
)
type GetUniqueRandomIntegersInput struct {
SizeX int
SizeY int
RandomLimit int
}
func (i GetUniqueRandomIntegersInput) Validate() error {
if i.SizeX <= 0 || i.SizeY <= 0 {
return errors.New("array length can't be negative or 0")
}
if i.RandomLimit <= 0 {
return errors.New("random limit can't be 0")
}
if i.RandomLimit < i.SizeX*i.SizeY {
return errors.New(
fmt.Sprintf("can't generate unique numbers with limit %d for %dx%d sized array",
i.RandomLimit, i.SizeX, i.SizeY))
}
return nil
}
type Randomizer struct {
uniqueIntegers map[int]bool
}
func NewRandomizer() *Randomizer {
rand.Seed(time.Now().Unix())
return &Randomizer{
uniqueIntegers: make(map[int]bool),
}
}
func (r *Randomizer) GetUniqueRandomIntegers(input GetUniqueRandomIntegersInput) ([]int, error) {
if err := input.Validate(); err != nil {
return nil, err
}
r.reset()
numbersCount := input.SizeX * input.SizeY
result := make([]int, 0)
for len(r.uniqueIntegers) < numbersCount {
r.uniqueIntegers[r.getRandomInt(input.RandomLimit)] = true
}
for num := range r.uniqueIntegers {
result = append(result, num)
}
return result, nil
}
func (r *Randomizer) reset() {
r.uniqueIntegers = make(map[int]bool)
}
func (r *Randomizer) getRandomInt(limit int) int {
return rand.Intn(limit)
}