// CMSC 341 - Fall 2019 - Project 5
// heap.h
// Templated, vector-based heap implementation

// To work with Heap, the template class T must provide the following:
//  (a) Default constructor
//  (b) priority function (unsigned priority())
//  (c) overloaded insertion operator
// To work with Heap *and* HashTable, it also needs:
//  (d) key function (string key())

#ifndef _HEAP_H
#define _HEAP_H

#include <iostream>
#include <vector>
#include <exception>
#include <utility>   // swap

using std::vector;
using std::endl;
using std::cout;
using std::swap;
using std::range_error;

// To work with Heap and HashTable, class T must provide the
// following:
//  (a) Default constructor
//  (b) priority function (unsigned priority())
//  (c) key function (string key())
//  (d) overloaded insertion operator

class Grader;

template <class T>
class Heap {

  friend Grader;
  
 public:
  // Constructor
  Heap();

  // Inline functions: size, empty, used 
  unsigned size() const { return _heap.size() - 1 ; }
  bool empty() const { return _heap.size() <= 1 ; }
  bool used() const { return _used ; }

  // Main heap operations: insert, read, remove
  void insert(const T& object);
  T readTop() const;
  void removeTop();

  // Dump the entire heap
  void dump() const;

  // Root node always has index 1
  static const unsigned ROOT = 1;
  
 private:
  vector<T> _heap;   // Vector-based heap
  bool _used;        // Has the heap ever been used?  Needed for
		     // linear probing.

  // *********************************************
  // Private helper function declarations go here!
  // *********************************************

};

// ***************************************
// Templated function definitions go here!
// ***************************************

#endif