deba@1623: /* -*- C++ -*-
deba@1623:  * lemon/grid_graph.h - Part of LEMON, a generic C++ optimization library
deba@1623:  *
deba@1623:  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
deba@1623:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
deba@1623:  *
deba@1623:  * Permission to use, modify and distribute this software is granted
deba@1623:  * provided that this copyright notice appears in all copies. For
deba@1623:  * precise terms see the accompanying LICENSE file.
deba@1623:  *
deba@1623:  * This software is provided "AS IS" with no warranty of any kind,
deba@1623:  * express or implied, and with no claim as to its suitability for any
deba@1623:  * purpose.
deba@1623:  *
deba@1623:  */
deba@1623: 
deba@1623: #ifndef GRID_GRAPH_H
deba@1623: #define GRID_GRAPH_H
deba@1623: 
deba@1623: #include <iostream>
deba@1623: #include <lemon/invalid.h>
deba@1623: #include <lemon/utility.h>
deba@1623: 
deba@1623: #include <lemon/bits/iterable_graph_extender.h>
deba@1623: #include <lemon/bits/alteration_notifier.h>
deba@1623: #include <lemon/bits/default_map.h>
deba@1623: 
deba@1623: #include <lemon/bits/undir_graph_extender.h>
deba@1623: 
deba@1623: namespace lemon {
deba@1623: 
deba@1623:   class GridGraphBase {
deba@1623: 
deba@1623:   public:
deba@1623: 
deba@1623:     typedef GridGraphBase Graph;
deba@1623: 
deba@1623:     class Node;
deba@1623:     class Edge;
deba@1623: 
deba@1623:   public:
deba@1623: 
deba@1623:     GridGraphBase() {}
deba@1623: 
deba@1623:   protected:
deba@1623: 
deba@1623:     /// \brief Creates a grid graph with the given size.
deba@1623:     ///
deba@1623:     /// Creates a grid graph with the given size.
deba@1623:     void construct(int height, int width) {
deba@1623:       _height = height; _width = width;
deba@1623:       _nodeNum = height * width; _edgeNum = 2 * _nodeNum - width - height;
deba@1623:       _edgeLimit = _nodeNum - width;
deba@1623:     }
deba@1623: 
deba@1623:   public:
deba@1623:     
deba@1623:     /// \brief The node on the given position.
deba@1623:     /// 
deba@1623:     /// Gives back the node on the given position.
deba@1623:     Node operator()(int i, int j) const {
deba@1623:       return Node(i * _width + j);
deba@1623:     }
deba@1623: 
deba@1623:     /// \brief Gives back the row index of the node.
deba@1623:     ///
deba@1623:     /// Gives back the row index of the node.
deba@1623:     int row(Node n) const {
deba@1623:       return n.id / _width;
deba@1623:     }
deba@1623:     
deba@1623:     /// \brief Gives back the coloumn index of the node.
deba@1623:     ///
deba@1623:     /// Gives back the coloumn index of the node.
deba@1623:     int col(Node node) const {
deba@1623:       return n.id % _width;    
deba@1623:     }
deba@1623: 
deba@1623:     /// \brief Gives back the width of the graph.
deba@1623:     ///
deba@1623:     /// Gives back the width of the graph.
deba@1623:     int width() const {
deba@1623:       return _width;
deba@1623:     }
deba@1623: 
deba@1623:     /// \brief Gives back the height of the graph.
deba@1623:     ///
deba@1623:     /// Gives back the height of the graph.
deba@1623:     int height() const {
deba@1623:       return _height;
deba@1623:     }
deba@1623: 
deba@1623:     typedef True NodeNumTag;
deba@1623:     typedef True EdgeNumTag;
deba@1623: 
deba@1623:     ///Number of nodes.
deba@1623:     int nodeNum() const { return _nodeNum; }
deba@1623:     ///Number of edges.
deba@1623:     int edgeNum() const { return _edgeNum; }
deba@1623: 
deba@1623:     /// Maximum node ID.
deba@1623:     
deba@1623:     /// Maximum node ID.
deba@1623:     ///\sa id(Node)
deba@1623:     int maxId(Node = INVALID) const { return nodeNum() - 1; }
deba@1623:     /// Maximum edge ID.
deba@1623:     
deba@1623:     /// Maximum edge ID.
deba@1623:     ///\sa id(Edge)
deba@1623:     int maxId(Edge = INVALID) const { return edgeNum() - 1; }
deba@1623: 
deba@1623:     /// \brief Gives back the source node of an edge.
deba@1623:     ///    
deba@1623:     /// Gives back the source node of an edge.
deba@1623:     Node source(Edge e) const {
deba@1623:       if (e.id < _edgeLimit) {
deba@1623: 	return e.id;
deba@1623:       } else {
deba@1623: 	return (e.id - _edgeLimit) % (_width - 1) +
deba@1623: 	  (e.id - _edgeLimit) / (_width - 1) * _width;
deba@1623:       }
deba@1623:     }
deba@1623: 
deba@1623:     /// \brief Gives back the target node of an edge.
deba@1623:     ///    
deba@1623:     /// Gives back the target node of an edge.
deba@1623:     Node target(Edge e) const {
deba@1623:       if (e.id < _edgeLimit) {
deba@1623: 	return e.id + _width;
deba@1623:       } else {
deba@1623: 	return (e.id - _edgeLimit) % (_width - 1) +
deba@1623: 	  (e.id - _edgeLimit) / (_width - 1) * _width + 1;
deba@1623:       }
deba@1623:     }
deba@1623: 
deba@1623:     /// Node ID.
deba@1623:     
deba@1623:     /// The ID of a valid Node is a nonnegative integer not greater than
deba@1623:     /// \ref maxNodeId(). The range of the ID's is not surely continuous
deba@1623:     /// and the greatest node ID can be actually less then \ref maxNodeId().
deba@1623:     ///
deba@1623:     /// The ID of the \ref INVALID node is -1.
deba@1623:     ///\return The ID of the node \c v. 
deba@1623: 
deba@1623:     static int id(Node v) { return v.id; }
deba@1623:     /// Edge ID.
deba@1623:     
deba@1623:     /// The ID of a valid Edge is a nonnegative integer not greater than
deba@1623:     /// \ref maxEdgeId(). The range of the ID's is not surely continuous
deba@1623:     /// and the greatest edge ID can be actually less then \ref maxEdgeId().
deba@1623:     ///
deba@1623:     /// The ID of the \ref INVALID edge is -1.
deba@1623:     ///\return The ID of the edge \c e. 
deba@1623:     static int id(Edge e) { return e.id; }
deba@1623: 
deba@1623:     static Node fromId(int id, Node) { return Node(id);}
deba@1623:     
deba@1623:     static Edge fromId(int id, Edge) { return Edge(id);}
deba@1623: 
deba@1623:     typedef True FindEdgeTag;
deba@1623: 
deba@1623:     /// Finds an edge between two nodes.
deba@1623:     
deba@1623:     /// Finds an edge from node \c u to node \c v.
deba@1623:     ///
deba@1623:     /// If \c prev is \ref INVALID (this is the default value), then
deba@1623:     /// It finds the first edge from \c u to \c v. Otherwise it looks for
deba@1623:     /// the next edge from \c u to \c v after \c prev.
deba@1623:     /// \return The found edge or INVALID if there is no such an edge.
deba@1623:     Edge findEdge(Node u, Node v, Edge prev = INVALID) {
deba@1623:       if (prev != INVALID) return INVALID;
deba@1623:       if (v.id - u.id == _width) return Edge(u.id);
deba@1623:       if (v.id - u.id == 1 && u.id % _width < _width - 1) {
deba@1623: 	return Edge(u.id / _width * (_width - 1) +
deba@1623: 		    u.id % _width + _edgeLimit);
deba@1623:       }
deba@1623:       return INVALID;
deba@1623:     }
deba@1623:     
deba@1623:       
deba@1623:     class Node {
deba@1623:       friend class GridGraphBase;
deba@1623: 
deba@1623:     protected:
deba@1623:       int id;
deba@1623:       Node(int _id) { id = _id;}
deba@1623:     public:
deba@1623:       Node() {}
deba@1623:       Node (Invalid) { id = -1; }
deba@1623:       bool operator==(const Node node) const {return id == node.id;}
deba@1623:       bool operator!=(const Node node) const {return id != node.id;}
deba@1623:       bool operator<(const Node node) const {return id < node.id;}
deba@1623:     };
deba@1623:     
deba@1623: 
deba@1623: 
deba@1623:     class Edge {
deba@1623:       friend class GridGraphBase;
deba@1623:       
deba@1623:     protected:
deba@1623:       int id; 
deba@1623: 
deba@1623:       Edge(int _id) : id(_id) {}
deba@1623: 
deba@1623:     public:
deba@1623:       Edge() { }
deba@1623:       Edge (Invalid) { id = -1; }
deba@1623:       bool operator==(const Edge edge) const {return id == edge.id;}
deba@1623:       bool operator!=(const Edge edge) const {return id != edge.id;}
deba@1623:       bool operator<(const Edge edge) const {return id < edge.id;}
deba@1623:     };
deba@1623: 
deba@1623:     void first(Node& node) const {
deba@1623:       node.id = nodeNum() - 1;
deba@1623:     }
deba@1623: 
deba@1623:     static void next(Node& node) {
deba@1623:       --node.id;
deba@1623:     }
deba@1623: 
deba@1623:     void first(Edge& edge) const {
deba@1623:       edge.id = edgeNum() - 1;
deba@1623:     }
deba@1623: 
deba@1623:     static void next(Edge& edge) {
deba@1623:       --edge.id;
deba@1623:     }
deba@1623: 
deba@1623:     void firstOut(Edge& edge, const Node& node) const {
deba@1623:       if (node.id < _nodeNum - _width) {
deba@1623: 	edge.id = node.id;
deba@1623:       } else if (node.id % _width < _width - 1) {
deba@1623: 	edge.id = _edgeLimit + node.id % _width +
deba@1623: 	  (node.id / _width) * (_width - 1);
deba@1623:       } else {
deba@1623: 	edge.id = -1;
deba@1623:       }
deba@1623:     }
deba@1623: 
deba@1623:     void nextOut(Edge& edge) const {
deba@1623:       if (edge.id >= _edgeLimit) {
deba@1623: 	edge.id = -1;
deba@1623:       } else if (edge.id % _width < _width - 1) {
deba@1623: 	edge.id = _edgeLimit + edge.id % _width +
deba@1623: 	  (edge.id / _width) * (_width - 1);
deba@1623:       } else {
deba@1623: 	edge.id = -1;
deba@1623:       }
deba@1623:     }
deba@1623: 
deba@1623:     void firstIn(Edge& edge, const Node& node) const {
deba@1623:       if (node.id >= _width) {
deba@1623: 	edge.id = node.id - _width;
deba@1623:       } else if (node.id % _width > 0) {
deba@1623: 	edge.id = _edgeLimit + node.id % _width +
deba@1623: 	  (node.id / _width) * (_width - 1) - 1;
deba@1623:       } else {
deba@1623: 	edge.id = -1;
deba@1623:       }
deba@1623:     }
deba@1623:     
deba@1623:     void nextIn(Edge& edge) const {
deba@1623:       if (edge.id >= _edgeLimit) {
deba@1623: 	edge.id = -1;
deba@1623:       } else if (edge.id % _width > 0) {
deba@1623: 	edge.id = _edgeLimit + edge.id % _width +
deba@1623: 	  (edge.id / _width + 1) * (_width - 1) - 1;
deba@1623:       } else {
deba@1623: 	edge.id = -1;
deba@1623:       }
deba@1623:     }
deba@1623: 
deba@1623:   private:
deba@1623:     int _width, _height;
deba@1623:     int _nodeNum, _edgeNum;
deba@1623:     int _edgeLimit;
deba@1623:   };
deba@1623: 
deba@1623: 
deba@1623:   typedef UndirGraphExtender<GridGraphBase>
deba@1623:   UndirGridGraphBase;
deba@1623:   typedef AlterableUndirGraphExtender<UndirGridGraphBase> 
deba@1623:   AlterableGridGraphBase;
deba@1623:   typedef IterableUndirGraphExtender<AlterableGridGraphBase> 
deba@1623:   IterableGridGraphBase;
deba@1623:   typedef MappableUndirGraphExtender<IterableGridGraphBase> 
deba@1623:   MappableGridGraphBase;
deba@1623: 
deba@1623:   /// \ingroup graphs
deba@1623:   ///
deba@1623:   /// \brief Grid graph class
deba@1623:   ///
deba@1623:   /// This class implements a special graph type. The nodes of the
deba@1623:   /// graph can be indiced by two integer \c (i,j) value where \c i
deba@1623:   /// is in the \c [0,height) range and j is in the [0, width) range.
deba@1623:   /// Two nodes are connected in the graph if the indices differ only
deba@1623:   /// on one position and only one is the difference. 
deba@1623:   ///
deba@1623:   /// The graph can be indiced in the following way:
deba@1623:   /// \code
deba@1623:   /// GridGraph graph(h, w);
deba@1623:   /// GridGraph::NodeMap<int> val(graph); 
deba@1623:   /// for (int i = 0; i < graph.height(); ++i) {
deba@1623:   ///   for (int j = 0; j < graph.width(); ++j) {
deba@1623:   ///     val[graph(i, j)] = i + j;
deba@1623:   ///   }
deba@1623:   /// }
deba@1623:   /// \endcode
deba@1623:   ///
deba@1623:   /// The graph type is fully conform to the \ref concept::UndirGraph
deba@1623:   /// "Undirected Graph" concept.
deba@1623:   ///
deba@1623:   /// \author Balazs Dezso
deba@1623:   class GridGraph : public MappableGridGraphBase {
deba@1623:   public:
deba@1623:     
deba@1623:     GridGraph(int m, int n) { construct(m, n); }
deba@1623:   };
deba@1623: }
deba@1623: #endif