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18 lines
445 B
Swift
18 lines
445 B
Swift
// Copyright © 2023 Rangeproof Pty Ltd. All rights reserved.
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import Foundation
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public extension Collection {
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subscript(test index: Index) -> Element? {
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return (indices.contains(index) ? self[index] : nil)
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}
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}
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public extension Array {
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func allCombinations() -> [[Element]] {
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guard !isEmpty else { return [[]] }
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return Array(self[1...]).allCombinations().flatMap { [$0, ([self[0]] + $0)] }
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}
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}
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