51 lines
1.8 KiB
Swift
51 lines
1.8 KiB
Swift
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func pattern(position: Int) -> DropFirstSequence<AnySequence<Int>>
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{
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precondition(position >= 0)
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let repeats = position + 1
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let base = [0, 1, 0, -1]
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return repeating(base.flatMap { Array(repeating: $0, count: repeats) }).dropFirst()
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}
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func repeating<T: Sequence>(_ sequence: T) -> AnySequence<T.Element>
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{
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return AnySequence { () -> AnyIterator<T.Element> in
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var it = sequence.makeIterator()
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return AnyIterator { () -> T.Element? in
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if let value = it.next() {
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return value
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}
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it = sequence.makeIterator()
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return it.next()
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}
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}
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}
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func phase(_ input: [Int]) -> [Int] {
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var result: [Int] = []
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return input.indices.map { i in
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abs(zip(input, pattern(position: i)).reduce(0) { (accum: Int, value: (Int, Int)) -> Int in accum + value.0 * value.1 }) % 10
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}
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}
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let input = "59773419794631560412886746550049210714854107066028081032096591759575145680294995770741204955183395640103527371801225795364363411455113236683168088750631442993123053909358252440339859092431844641600092736006758954422097244486920945182483159023820538645717611051770509314159895220529097322723261391627686997403783043710213655074108451646685558064317469095295303320622883691266307865809481566214524686422834824930414730886697237161697731339757655485312568793531202988525963494119232351266908405705634244498096660057021101738706453735025060225814133166491989584616948876879383198021336484629381888934600383957019607807995278899293254143523702000576897358"
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var data: [Int] = input.map { $0.wholeNumberValue! }
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func readAt(_ index: Int) -> Int {
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data[index ..< index + 8].reduce(0) { 10 * $0 + $1 }
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}
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readAt(readAt(0))
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//for i in 0..<100 {
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// data = phase(data)
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//}
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//
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//print(data[0..<8])
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