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51 lines
1.3 KiB
51 lines
1.3 KiB
3 years ago
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package rand
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import (
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"math/rand"
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"sync"
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)
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// Int returns a non-negative pseudo-random int.
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func Int() int { return pseudo.Int() }
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// Intn returns, as an int, a non-negative pseudo-random number in [0,n).
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// It panics if n <= 0.
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func Intn(n int) int { return pseudo.Intn(n) }
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// Int63n returns, as an int64, a non-negative pseudo-random number in [0,n).
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// It panics if n <= 0.
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func Int63n(n int64) int64 { return pseudo.Int63n(n) }
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// Perm returns, as a slice of n ints, a pseudo-random permutation of the integers [0,n).
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func Perm(n int) []int { return pseudo.Perm(n) }
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// Seed uses the provided seed value to initialize the default Source to a
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// deterministic state. If Seed is not called, the generator behaves as if
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// seeded by Seed(1).
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func Seed(n int64) { pseudo.Seed(n) }
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var pseudo = rand.New(&source{src: rand.NewSource(1)})
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type source struct {
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src rand.Source
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mu sync.Mutex
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}
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func (s *source) Int63() int64 {
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s.mu.Lock()
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n := s.src.Int63()
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s.mu.Unlock()
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return n
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}
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func (s *source) Seed(seed int64) {
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s.mu.Lock()
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s.src.Seed(seed)
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s.mu.Unlock()
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}
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// Shuffle pseudo-randomizes the order of elements.
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// n is the number of elements.
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// swap swaps the elements with indexes i and j.
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func Shuffle(n int, swap func(i, j int)) { pseudo.Shuffle(n, swap) }
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