24 lines
501 B
Swift
24 lines
501 B
Swift
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func step(_ input: String) -> String {
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var position = input.startIndex
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var output = ""
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while position < input.endIndex {
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let next = input[position...].firstIndex(where: { $0 != input[position] }) ?? input.endIndex
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let distance = input.distance(from: position, to: next)
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output += "\(distance)\(input[position])"
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position = next
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}
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return output
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}
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var current = "1321131112"
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for _ in 0..<50 {
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current = step(current)
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}
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current
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current.count
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