Graph

public struct Graph<Vertex: Hashable, Edge>

A simple directed graph: that is, one with no loops (edges connected at both ends to the same vertex) and no more than one edge in the same direction between any two different vertices. All vertices in the graph are unique. Edges are not allowed to be generic types. The preferred way to acess and insert vertices or edges is using subscript notation. Example: graph["NY", "Boston"] = distance

Conforms to Sequence.

Creating a Graph

  • Creates an empty graph.

    Declaration

    Swift

    public init()

Querying a Graph

  • Number of vertices stored in the graph.

    Declaration

    Swift

    public var count: Int

  • Returns true if and only if count == 0.

    Declaration

    Swift

    public var isEmpty: Bool

  • Returns true if every pair of distinct vertices is connected by a unique edge (one in each direction).

    Declaration

    Swift

    public var isComplete: Bool

  • Returns true if there’s not a path starting and ending at the same vertex.

    Declaration

    Swift

    public var isAcyclic: Bool

  • Returns the vertices stored in the graph.

    Declaration

    Swift

    public var vertices: Set<Vertex>

  • Returns the edges stored in the graph.

    Declaration

    Swift

    public var edges: [Edge]

  • Returns true if the graph contains the given vertex.

    Declaration

    Swift

    public func containsVertex(_ vertex: Vertex) -> Bool

  • Returns true if the graph contains an edge from source to destination. Subscript notation is preferred.

    Declaration

    Swift

    public func containsEdgeFrom(_ source: Vertex, to destination: Vertex) -> Bool

  • Returns the edge connecting source to destination if it exists. Subscript notation is preferred.

    Declaration

    Swift

    public func edgeFrom(_ source: Vertex, to destination: Vertex) -> Edge?

  • Returns the set of direct successors of the given vertex. An empty set is returned if the vertex does not exist.

    Declaration

    Swift

    public func neighbors(_ source: Vertex) -> Set<Vertex>

  • Returns an array of vertices representing a path from source to destination, if it exists.

    Declaration

    Swift

    public func pathFrom(_ source: Vertex, to destination: Vertex) -> [Vertex]?

    Return Value

    An array containing at least two vertices (source and destination) or nil.

  • Returns a generator iterating over the vertices in the specified order starting at the given vertex. Valid options are .DepthFirst and .BreadthFirst.

    The generator never returns the same vertex more than once.

    Declaration

    Swift

    public func generateAt(_ source: Vertex, order: GraphTraversalOrder) -> AnyIterator<Vertex>

Adding and Removing Elements

  • Inserts the given vertex to the graph if it doesn’t exist.

    Declaration

    Swift

    public mutating func insertVertex(_ vertex: Vertex)

  • Removes and returns the given vertex from the graph if it was present.

    Declaration

    Swift

    public mutating func removeVertex(_ vertex : Vertex) -> Vertex?

  • Connects two vertices with the given edge. If an edge already exists, it is replaced. Subscript notation is preferred.

    Declaration

    Swift

    public mutating func insertEdge(_ edge: Edge, from source: Vertex, to destination: Vertex)

  • Removes and returns the edge connecting the given vertices if it exists.

    Declaration

    Swift

    public mutating func removeEdgeFrom(_ source: Vertex, to destination: Vertex) -> Edge?

  • Removes all vertices and edges from the graph, and by default clears the underlying storage buffer.

    Declaration

    Swift

    public mutating func removeAll(keepingCapacity keep: Bool = false)

Sequence Protocol Conformance

  • Provides for-in loop functionality.

    Declaration

    Swift

    public func makeIterator() -> AnyIterator<Vertex>

    Return Value

    A generator over the vertices.