46 lines
917 B
Text
46 lines
917 B
Text
func shuffle(arr) {
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if arr.Length() % 2 != 0 {
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throw @InvalidValue(arr.Length())
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}
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var half = arr.Length() / 2
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var result = Array.Empty(arr.Length())
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var (t, l, r) = (0, 0, half)
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while l < half {
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result[t] = arr[l]
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result[t+1] = arr[r]
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l += 1
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r += 1
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t += 2
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}
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result
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}
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func arrayEqual(xs, ys) {
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if xs.Length() != ys.Length() {
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return false
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}
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for i in xs.Indices() {
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if xs[i] != ys[i] {
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return false
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}
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}
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return true
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}
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func shuffleThrough(original) {
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var copy = original.Clone()
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while true {
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copy = shuffle(copy)
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yield copy
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if arrayEqual(original, copy) {
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break
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}
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}
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}
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for input in yields { 8, 24, 52, 100, 1020, 1024, 10000} {
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var numbers = [1..input]
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print("\(input) cards: \(shuffleThrough(numbers).Length())")
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}
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