include "heap.h"

Heap::Heap(vector<int>& vec)
{
    h = vec;
    for(int i = (int)h.size()/2; i >=0; i--)
    {
        correct(i);
    }

}

void Heap::add(int value)
{
    h.push_back(value);
    int current_index = h.size() - 1;
    int parent = (current_index - 1)/2;
    while(h[current_index] > h[parent])
    {
        swap(h[current_index], h[parent]);
        current_index = parent;
        parent = (parent - 1)/2;
    }
}

void Heap::pop()
{

    std::swap(h[0], h[h.size()-1]);
    h.erase(h.begin() + h.size()-1);
    correct(0);

}

void Heap::print()
{
    for(int i = 0; i < h.size(); i++)
    {
        cout << h[i] << " ";
    }
    cout << endl;
}

void Heap::correct(int index)
{
    unsigned left_index,right_index,biggest_child;
    while(1)
    {
        left_index=2*index+1;
        right_index=2*index+2;
        biggest_child=index;
        if(left_index<h.size()&&h[left_index]>h[biggest_child])
        {
            biggest_child=left_index;
        }
        if(right_index<h.size()&&h[right_index]>h[biggest_child])
        {
            biggest_child=right_index;
        }
        if(biggest_child==index)
            break;
        swap(h[index],h[biggest_child]);
        index=biggest_child;
    }
}

void Heap::increase(int index, int change)
{
    if(index >= h.size() || index < 0 || change < 0)
    {
        throw exception();
    }
    h[index] += change;
    int current_index = index;
    int parent = (current_index - 1)/2;
    while(h[current_index] > h[parent])
    {
        swap(h[current_index], h[parent]);
        current_index = parent;
        parent = (parent - 1)/2;
    }
}

void Heap::decrement(int index, int change)
{
    if(index >= h.size() || index < 0 || change < 0)
    {
        throw exception();
    }
     h[index] -= change;
    correct(index);
}