Submission #564494

#	Time	Username	Problem	Language	Result	Execution time	Memory
564494		Stickfish	Intergalactic ship (IZhO19_xorsum)	C++17	92 / 100	2075 ms	3648 KiB

xorsum

#include <iostream>
#include <vector>
#include <bitset>
using namespace std;
using ll = long long;

const int MAXN = 1008;
const ll MOD = 1000000007;
const int MAXVAL = 128;
int a[MAXN];

void updt(bitset<MAXVAL>& bs, int t) {
    if (bs[bs._Find_first() ^ t])
        return;
    vector<int> it;
    for (int i = bs._Find_first(); i < MAXVAL; i = bs._Find_next(i)) {
        it.push_back(i ^ t);
    }
    for (auto i : it)
        bs[i] = 1;
}

ll pw(ll a, ll m) {
    if (!m)
        return 1;
    a %= MOD;
    if (m % 2)
        return a * pw(a, m - 1) % MOD;
    return pw(a * a, m / 2);
}

bool in(pair<int, int> sg, int i) {
    return sg.first <= i && i < sg.second;
}

vector<pair<int, int>> events[MAXN];

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n;
    cin >> n;
    for (int i = 0; i < n; ++i)
        cin >> a[i];
    int q;
    cin >> q;
    for (int i = 0; i < q; ++i) {
        int l, r, x;
        cin >> l >> r >> x;
        --l;
        events[l].push_back({r, x});
        events[r].push_back({l, x});
    }
    ll ans = 0;
    vector<int> genij0(MAXVAL, 0);
    bitset<MAXVAL> genbsij0;
    for (int i = 0; i < n; ++i) {
        for (auto [e, x] : events[i]) {
            if (e < i)
                genbsij0[x] = --genij0[x];
            else
                genbsij0[x] = ++genij0[x];
        }
        vector<int> geni(MAXVAL);
        bitset<MAXVAL> genbsi;
        vector<int> genj(MAXVAL);
        bitset<MAXVAL> genbsj;
        vector<int> genij = genij0;
        bitset<MAXVAL> genbsij = genbsij0;

        for (int j = i; j < n; ++j) {
            if (j > i) {
                for (auto [e, x] : events[j]) {
                    if (e <= i) {
                        genbsij[x] = --genij[x];
                        genbsi[x] = ++geni[x];
                    } else if (e < j) {
                        genbsj[x] = --genj[x];
                    } else {
                        genbsj[x] = ++genj[x];
                    }
                }
            }
            bitset<MAXVAL> bsi;
            bitset<MAXVAL> bsj;
            bitset<MAXVAL> bsij;
            bsi[a[i]] = bsj[a[j]] = bsij[0] = 1;
            //cout << "---" << i << ' ' << j << "---\n";
            for (int xi = genbsi._Find_first(); xi < MAXVAL; xi = genbsi._Find_next(xi)) {
                //cout << xi << ' ';
                updt(bsi, xi);
            }
            //cout << endl;
            for (int xj = genbsj._Find_first(); xj < MAXVAL; xj = genbsj._Find_next(xj)) {
                //cout << xj << ' ';
                updt(bsj, xj);
            }
            //cout << endl;
            for (int xij = genbsij._Find_first(); xij < MAXVAL; xij = genbsij._Find_next(xij)) {
                //cout << xij << ' ';
                updt(bsij, xij);
            }
            //cout << endl;
            ll addans = 0;
            vector<int> xj_from_xij(MAXVAL);
            for (int xij = bsij._Find_first(); xij < MAXVAL; xij = bsij._Find_next(xij)) {
                if (bsj.count() == 128) {
                    xj_from_xij[xij] = 64 * 127;
                } else {
                    for (int xj = bsj._Find_first(); xj < MAXVAL; xj = bsj._Find_next(xj)) {
                        xj_from_xij[xij] += xj ^ xij;
                    }
                }
            }
            if (i != j) {
                for (int xij = bsij._Find_first(); xij < MAXVAL; xij = bsij._Find_next(xij)) {
                    xj_from_xij[xij] *= 2;
                }
            }
            for (int xij = bsij._Find_first(); xij < MAXVAL; xij = bsij._Find_next(xij)) {
                if (bsi.count() == 128) {
                    addans += xj_from_xij[xij] * 64 * 127;
                } else {
                    for (int xi = bsi._Find_first(); xi < MAXVAL; xi = bsi._Find_next(xi)) {
                        addans += xj_from_xij[xij] * (xi ^ xij);
                    }
                }
                addans %= MOD;
            }
            addans *= (i + 1) * (n - j);
            addans %= MOD;
            addans *= pw(2, q);
            addans %= MOD;
            //cout << bsi.count() << ' ' << bsj.count() << ' ' << bsij.count() << endl;
            addans *= pw(bsi.count() * bsj.count() * bsij.count(), MOD - 2);
            ans += addans;
            ans %= MOD;
            //cout << i << ' ' << j << ": " << ans - ans0 << endl;
        }
    }
    cout << ans << endl;
}

• Subtask 1: 4 / 4
• Subtask 2: 5 / 5
• Subtask 3: 6 / 6
• Subtask 4: 9 / 9
• Subtask 5: 8 / 8
• Subtask 6: 11 / 11
• Subtask 7: 19 / 19
• Subtask 8: 30 / 30
• Subtask 9: 0 / 8