Submission #465998

#	Time	Username	Problem	Language	Result	Execution time	Memory
465998		SamAnd	Xor Sort (eJOI20_xorsort)	C++17	65 / 100	12 ms	1292 KiB

xorsort

#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937 rnf(2106);
const int N = 1003, m = 20;

int n, ty;
int a[N];

vector<pair<int, int> > ans;
void ubd(int x, int y)
{
    ans.push_back(m_p(x, y));
    a[x] ^= a[y];
}

void solv2()
{
    int nn = n;
    for (int j = m - 1; j >= 0; --j)
    {
        for (int i = 1; i < nn; ++i)
        {
            if ((a[i] & (1 << j)))
            {
                if ((a[i + 1] & (1 << j)))
                    ubd(i, i + 1);
                else
                {
                    ubd(i + 1, i);
                    ubd(i, i + 1);
                }
            }
        }
        if ((a[nn] & (1 << j)))
            --nn;
    }

    for (int i = 1; i < n; ++i)
        assert(a[i] <= a[i + 1]);
}

void solv1()
{
    for (int ii = 0; ii < n; ++ii)
    {
        for (int i = 1; i < n; ++i)
        {
            if (a[i + 1] < a[i])
            {
                ubd(i, i + 1);
                ubd(i + 1, i);
                ubd(i, i + 1);
            }
        }
    }

    for (int i = 1; i < n; ++i)
        assert(a[i] < a[i + 1]);
}

void solv()
{
    cin >> n >> ty;
    for (int i = 1; i <= n; ++i)
        cin >> a[i];

    if (ty == 2)
    {
        solv2();
    }
    else
    {
        solv1();
    }

    cout << sz(ans) << "\n";
    for (int i = 0; i < sz(ans); ++i)
        cout << ans[i].fi << ' ' << ans[i].se << "\n";
}

int main()
{
    #ifdef SOMETHING
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    #endif // SOMETHING
    ios_base::sync_with_stdio(false), cin.tie(0);

    int tt = 1;
    //cin >> tt;
    while (tt--)
    {
        solv();
    }
    return 0;
}

• Subtask 1: 25 / 25
• Subtask 2: 0 / 35
• Subtask 3: 40 / 40