Submission #1092366

#	Time	Username	Problem	Language	Result	Execution time	Memory
1092366		efishel	Xor Sort (eJOI20_xorsort)	C++17	100 / 100	5 ms	1496 KiB

xorsort

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector <ll>;
using ii = pair <ll, ll>;
using vii = vector <ii>;
 
const ll MAXN = 1E3+16;
ll th[MAXN];
vii ans;
vll ve;
void fop (ll i, ll j) {
    ans.push_back({ i, j });
    ve[i] ^= ve[j];
}
 
int main () {
    cin.tie(nullptr) -> sync_with_stdio(false);
    ll n, s;
    cin >> n >> s;
    if (s == 2) {
        ve = vll(n);
        for (ll &i : ve) cin >> i;
        ll nend = n;
        for (ll bit = 19; bit >= 0; bit--) {
            vll th = ve;
            for (ll &i : th) i = i>>bit&1;
            ll j = find(th.begin(), th.begin()+nend, 1) - th.begin();
            for (ll i = j+1; i < nend; i++) {
                if (th[i]) continue;
                fop(i, i-1);
            }
            for (ll i = j+1; i < nend; i++) {
                fop(i-1, i);
            }
            if (j != nend) nend--;
        }
        cout << ans.size() << '\n';
        for (auto [i, j] : ans) cout << i+1 << ' ' << j+1 << '\n';
        return 0;
    }
    vll ve(n);
    for (ll &i : ve) cin >> i;
    ::ve = ve;
    for (ll in = n; in >= 1; in--) {
        for (ll i = 0; i < in-1; i++) {
            fop(i, i+1);
        }
        ll j = max_element(ve.begin(), ve.begin()+in) - ve.begin();
        for (ll i = j+1; i < in; i++) {
            fop(i, i-1);
        }
        for (ll i = j-2; i >= 0; i--) {
            fop(i, i+1);
        }
        ve.erase(ve.begin()+j);
    }
    for (ll i = n-2; i >= 0; i--) {
        fop(i, i+1);
    }
    cout << ans.size() << '\n';
    for (auto [i, j] : ans) cout << i+1 << ' ' << j+1 << '\n';
    return 0;
}

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