30 lines
933 B
Swift
30 lines
933 B
Swift
import Foundation
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func readInput(filePath: String) -> [[Int?]]? {
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let content = try? String(contentsOfFile: filePath, encoding: .ascii)
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let lines = content?.split(separator: "\n")
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return lines?.map { $0.split(separator: " ").map { Int($0) } }
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}
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func safe(_ report: [Int?]) -> Bool {
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if report.contains(nil) {
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return false
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}
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let diffs = zip(report.dropFirst(), report).map { $0.0! - $0.1! }
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return diffs.allSatisfy { abs($0) >= 1 }
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&& diffs.allSatisfy { abs($0) <= 3 }
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&& (diffs.allSatisfy { $0 > 0 } || diffs.allSatisfy { 0 > $0 })
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}
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func drop<T>(_ l: [T], at: Int) -> [T] {
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return l.enumerated().filter { $0.0 != at }.map { $0.1 }
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}
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func mutate<T>(_ l: [T]) -> [[T]] {
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return (0..<l.count).map { drop(l, at: $0) }
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}
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let reports = readInput(filePath: CommandLine.arguments[1])
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let answer = reports!.map(mutate).filter { $0.contains(where: safe) }.count
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print(answer)
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