Heap (Heap Sort)

#include <iostream>
#include <vector>

using namespace std;

void rep(vector <int>& v, int p, int top)
{
    int l = 2 * p + 1;
    int r = 2 * p + 2;
    if (top <= l)
        return;
    if (top == l + 1)
        r = l;
    int imax = v[l] > v[r] ? l : r;
    if (v[imax] > v[p])
        swap(v[imax], v[p]);
    rep(v, imax, top);
}

int main()
{
    vector <int> a;
    for (int i = 0; i < 10; i++)
    {
        a.push_back(i);
        cout << a[i] << " ";
    }
    cout << endl;

    for (int i = (int)a.size() / 2; i >= 0; i--)
        rep(a, i, (int)a.size());

    for (int i = 0; i < 10; i++)
        cout << a[i] << " ";
    cout << endl;

    for (int i = (int)a.size() - 1; i > 0; i--)
    {
        swap(a[0], a[i]);
        rep(a, 0, i);
    }

    for (int i = 0; i < 10; i++)
        cout << a[i] << " ";
    return 0;
}