42 lines
1.2 KiB
Swift
42 lines
1.2 KiB
Swift
import Foundation
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enum Color: Character, CustomStringConvertible {
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case r = "r"
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case g = "g"
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case u = "u"
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case w = "w"
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case b = "b"
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var description: String { return String(self.rawValue) }
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}
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func readInput(_ filePath: String) throws -> ([[Color]], [[Color]]) {
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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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let towels = lines[0].split(separator: ", ").map { $0.compactMap(Color.init) }
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let patterns = lines[1..<lines.count].map { $0.compactMap(Color.init) }
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return (towels, patterns)
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}
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var cache: [[Color]: Bool] = [:]
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func canMatch(_ pattern: [Color], _ towels: [[Color]]) -> Bool {
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if pattern.count == 0 {
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return true
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}
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if let cached = cache[pattern] {
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return cached
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}
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for towel in towels {
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if pattern.starts(with: towel) {
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if canMatch(Array(pattern[towel.count..<pattern.count]), towels) {
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cache[pattern] = true
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return true
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}
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}
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}
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cache[pattern] = false
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return false
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}
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let (towels, patterns) = try readInput(CommandLine.arguments[1])
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print(patterns.filter { canMatch($0, towels) }.count)
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