e94d758a9b
* move random generator into Settings * add empty and royale maps * place snakes on either cardinal or corner positions first
76 lines
1.3 KiB
Go
76 lines
1.3 KiB
Go
package rules
|
|
|
|
import "math/rand"
|
|
|
|
type Rand interface {
|
|
Intn(n int) int
|
|
Shuffle(n int, swap func(i, j int))
|
|
}
|
|
|
|
// A Rand implementation that just uses the global math/rand generator.
|
|
var GlobalRand globalRand
|
|
|
|
type globalRand struct{}
|
|
|
|
func (globalRand) Intn(n int) int {
|
|
return rand.Intn(n)
|
|
}
|
|
|
|
func (globalRand) Shuffle(n int, swap func(i, j int)) {
|
|
rand.Shuffle(n, swap)
|
|
}
|
|
|
|
type seedRand struct {
|
|
seed int64
|
|
rand *rand.Rand
|
|
}
|
|
|
|
func NewSeedRand(seed int64) *seedRand {
|
|
return &seedRand{
|
|
seed: seed,
|
|
rand: rand.New(rand.NewSource(seed)),
|
|
}
|
|
}
|
|
|
|
func (s seedRand) Intn(n int) int {
|
|
return s.rand.Intn(n)
|
|
}
|
|
|
|
func (s seedRand) Shuffle(n int, swap func(i, j int)) {
|
|
s.rand.Shuffle(n, swap)
|
|
}
|
|
|
|
// For testing purposes
|
|
|
|
// A Rand implementation that always returns the minimum value for any method.
|
|
var MinRand minRand
|
|
|
|
type minRand struct{}
|
|
|
|
func (minRand) Intn(n int) int {
|
|
return 0
|
|
}
|
|
|
|
func (minRand) Shuffle(n int, swap func(i, j int)) {
|
|
// no shuffling
|
|
}
|
|
|
|
// A Rand implementation that always returns the maximum value for any method.
|
|
var MaxRand maxRand
|
|
|
|
type maxRand struct{}
|
|
|
|
func (maxRand) Intn(n int) int {
|
|
return n - 1
|
|
}
|
|
|
|
func (maxRand) Shuffle(n int, swap func(i, j int)) {
|
|
// rotate by one element so every element is moved
|
|
if n < 2 {
|
|
return
|
|
}
|
|
for i := 0; i < n-2; i++ {
|
|
swap(i, i+1)
|
|
}
|
|
swap(n-2, n-1)
|
|
}
|