кастрированные алгоритмы

#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
using namespace std;

struct sort_net
{
    int n;
    vector<vector<pair<int, int> > > sn;
    sort_net()
    {

    }
    sort_net(int n, vector<vector<pair<int, int> > > sn)
    {
        this->n = n;
        this->sn = sn;
    }
    bool check(vector<int> &v)
    {
        for (int i = 0; i < sn.size(); i++)
        {
            for (int j = 0; j < sn[i].size(); j++)
            {
                if (v[sn[i][j].first] > v[sn[i][j].second])
                    swap(v[sn[i][j].first], v[sn[i][j].second]);
            }
        }
        for (int i = 1; i < v.size(); i++)
            if (v[i] < v[i - 1])
                return false;
        return true;
    }
    bool is_sorting()
    {
        vector<int> t(n);
        for (int i = 0; i < (1 << n); i++)
        {
            for (int j = 0; j < n; j++)
                t[j] = (i >> j) & 1;

            if (!check(t))
                return false;
        }
        return true;
    }
    void print()
    {
        int comps = 0;
        int layers = 0;
        for (int i = 0; i < sn.size(); i++)
        {
            comps += sn[i].size();
            if (sn[i].size() > 0)
                layers++;
        }
        cout << n << " " << comps << " " << layers << endl;
        for (int i = 0; i < sn.size(); i++)
        {
            if (sn[i].size() == 0)
                continue;
            printf("%d ", sn[i].size());
            for (int j = 0; j < sn[i].size(); j++)
                printf("%d %d ", sn[i][j].first + 1, sn[i][j].second + 1);
            printf("\n");
        }
    }
};

vector<vector<pair<int, int> > > sn;

int build_merger(vector<int> v, int d)
{
    if (v.size() <= 1)
        return d;
    if (v.size() == 2)
    {
        sn[d].push_back(make_pair(v[0], v[1]));
        return d + 1;
    }
    vector<int> odd;
    vector<int> even;
    int sz = v.size();
    for (int i = 0; i < sz / 2; i++)
    {
        if (i % 2 == 0)
            even.push_back(v[i]);
        else
            odd.push_back(v[i]);
    }
    for (int i = sz / 2; i < sz; i++)
    {
        if (i % 2 == 0)
            even.push_back(v[i]);
        else
            odd.push_back(v[i]);
    }

    int d1 = build_merger(odd, d);
    int d2 = build_merger(even, d);
    int md = max(d1, d2);
    for (int i = 1; i < v.size(); i += 2)
    {
        if (i + 1 < v.size())
        {
            sn[md].push_back(make_pair(v[i], v[i + 1]));
        }
    }
    return md + 1;
}

int build_sorter(int l, int r, int d)//âåðíåò ãëóáèíó
{
    if (l + 1 > r)
        return d;
    if (l + 1 == r)
    {
        sn[d].push_back(make_pair(l, r));
        return d + 1;
    }
    int sz = r - l + 1;
    int d1 = build_sorter(l, l + sz / 2 - 1, d);
    int d2 = build_sorter(l + sz / 2, r, d);
    int md = max(d1, d2);
    vector<int> v;
    for (int i = l; i <= r; i++)
        v.push_back(i);

    int rd = build_merger(v, md);
    return rd;
}

void build_net(int n)
{
    sn.clear();
    sn.resize(20);

    int p2 = 1;
    while (p2 < n)
        p2 *= 2;
    build_sorter(0, p2 - 1, 0);

    while (sn.size() > 0 && sn.back().empty())
        sn.pop_back();


    for (int i = 0; i < sn.size(); i++)
    {
        vector<pair<int, int> > filt;
        for (int j = 0; j < sn[i].size(); j++)
        {
            if (sn[i][j].first < n && sn[i][j].second < n)
                filt.push_back(sn[i][j]);
        }
        sn[i] = filt;
    }

    sort_net(n, sn).print();
}

bool test(int n)
{
    sn.clear();
    sn.resize(20);

    int p2 = 1;
    while (p2 < n)
        p2 *= 2;
    build_sorter(0, p2 - 1, 0);

    while (sn.size() > 0 && sn.back().empty())
        sn.pop_back();

    for (int i = 0; i < sn.size(); i++)
    {
        vector<pair<int, int> > filt;
        for (int j = 0; j < sn[i].size(); j++)
        {
            if (sn[i][j].first < n && sn[i][j].second < n)
                filt.push_back(sn[i][j]);
        }
        sn[i] = filt;
    }

    sort_net checker(n, sn);
    if (checker.is_sorting())
        return true;
    else
        return false;
}

int main()
{
    /*
    for (int i = 1; i <= 16; i++)
    {
        if (!test(i))
            cerr << "i = " << i << "  : PICHALKA" << endl;
    }
    return 0;
    sn.resize(20);
    */
    freopen("netbuild.in", "r", stdin);
    freopen("netbuild.out", "w", stdout);
    int n;
    cin >> n;
    build_net(n);
    return 0;
}