// Test of closest pair algorithms
// David Eppstein, UC Irvine, 19 Apr 1997
//
// Programmer interface for closest pair data structures
// (maintain a set of points and find two distinct points at minimum distance).
//
// Actual implementations will be subclassed from this outline.

#ifndef CLOSEST_PAIRS_H
#define CLOSEST_PAIRS_H

#include "Distances.h"

// For instrumentation purposes, we keep track of the
// number of times each data structure operation is performed.
// Initial values in the constructor also count as insertions.
//
// We don't update these values in the base class's stub constructor
// because that might screw up the counts when it is automatically called.
//
extern unsigned long gInsertions;
extern unsigned long gDeletions;
extern unsigned long gPairs;

class ClosestPairs {
 public:
 	virtual ~ClosestPairs() { ; }
 	ClosestPairs(long npoints, long max_points, Distance & d) { ; }
 		// Constructor takes as args number of points currently in struc,
 		// max number that will ever be in struc, and how to measure distances.
 		// Initially the point set consists of points represented by
 		// the numbers 0, 1, 2, ..., npoints - 2, npoints - 1.
 	
 	virtual void operator += (point) { gInsertions++; }
 		// Procedure to include another point in the data structure.
 		// The effect is undefined if the given point is already in the struc.
 	
 	virtual void operator -= (point) { gDeletions++; }
 		// Procedure to remove a point from the data structure.
 		// The effect is undefined if the given point isn't in the struc.

 	virtual double operator() (point & a, point & b) { gPairs++; }
 		// Find the two closest points and return them in the given var args
 		// Return the distance between them (to avoid caller having to recompute)
 	
 	// and now two functions for informing the CP data struc that although
 	// the points are unchanged, the distance function has been changed
 	virtual void UpdatePoint(point) { ; }
 	virtual void UpdateDistance(point,point) { ; }
};

#endif