MinHeap.hh

//STARTHEADER
// $Id: MinHeap.hh 1761 2010-09-16 10:43:18Z soyez $
//
// Copyright (c) 2005-2006, Matteo Cacciari and Gavin Salam
//
//----------------------------------------------------------------------
// This file is part of FastJet.
//
//  FastJet is free software; you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation; either version 2 of the License, or
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//  The algorithms that underlie FastJet have required considerable
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//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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#ifndef __FASTJET_MINHEAP__HH__
#define __FASTJET_MINHEAP__HH__

#include<vector>
#include<cassert>
#include<memory>
#include<limits>
#include "fastjet/internal/base.hh"

FASTJET_BEGIN_NAMESPACE      // defined in fastjet/internal/base.hh

//======================================================================
class MinHeap {
public:
  MinHeap (const std::vector<double> & values, unsigned int max_size) :
    _heap(max_size) {_initialise(values);};

  MinHeap (const std::vector<double> & values) :
    _heap(values.size()) {_initialise(values);};
  
  inline unsigned int minloc() const {
    return (_heap[0].minloc) - &(_heap[0]);};
  
  inline double       minval() const {return _heap[0].minloc->value;};

  inline double operator[](int i) const {return _heap[i].value;};

  void remove(unsigned int loc) {
    update(loc,std::numeric_limits<double>::max());};

  void update(unsigned int, double);

private:

  struct ValueLoc{
    double value;
    ValueLoc * minloc;
  };
      
  std::vector<ValueLoc> _heap;

  void _initialise(const std::vector<double> & values);


};


FASTJET_END_NAMESPACE

#endif // __FASTJET_MINHEAP__HH__