Doubly-linked list/Element insertion: Difference between revisions
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} |
} |
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}</lang> |
}</lang> |
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=={{header|Swift}}== |
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<lang swift>typealias NodePtr<T> = UnsafeMutablePointer<Node<T>> |
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class Node<T> { |
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var value: T |
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fileprivate var prev: NodePtr<T>? |
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fileprivate var next: NodePtr<T>? |
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init(value: T, prev: NodePtr<T>? = nil, next: NodePtr<T>? = nil) { |
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self.value = value |
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self.prev = prev |
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self.next = next |
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} |
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} |
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@discardableResult |
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func insert<T>(_ val: T, after: Node<T>? = nil, list: NodePtr<T>? = nil) -> NodePtr<T> { |
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let node = NodePtr<T>.allocate(capacity: 1) |
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node.initialize(to: Node(value: val)) |
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var n = list |
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while n != nil { |
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if n?.pointee !== after { |
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n = n?.pointee.next |
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continue |
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} |
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node.pointee.prev = n |
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node.pointee.next = n?.pointee.next |
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n?.pointee.next?.pointee.prev = node |
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n?.pointee.next = node |
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break |
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} |
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return node |
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} |
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// [1] |
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let list = insert(1) |
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// [1, 2] |
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insert(2, after: list.pointee, list: list) |
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// [1, 3, 2] |
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insert(3, after: list.pointee, list: list)</lang> |
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=={{header|Tcl}}== |
=={{header|Tcl}}== |
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