Submission #1230308

#	Time	Username	Problem	Language	Result	Execution time	Memory
1230308		RakhimovAmir	Spring cleaning (CEOI20_cleaning)	C++20	100 / 100	138 ms	17732 KiB

cleaning

#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
inline void debugMode() {
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif // ONLINE_JUDGE
}

const int N = 1e5 + 10;
vector<int> v[N];
int n, q;
int c[N], add[N], f[N], p[N], tin[N], tout[N], tt, st[N], sz[N], t[4 * N][2], upd[4 * N], rev[N], k;
int res, root;

void trace(int x, int p) {
    tin[x] = ++tt;
    int big = -1;
    for (auto to : v[x]) {
        if (to == p) {
            continue;
        }
        if (big == -1 || sz[to] > sz[big]) {
            big = to;
        }
    }
    // cout << x << " -> " << big << "\n";
    if (big != -1) {
        st[big] = st[x];
        trace(big, x);
    }
    for (auto to : v[x]) {
        if (to == p || to == big) {
            continue;
        }
        st[to] = to;
        trace(to, x);
    }
    tout[x] = tt;
}

void build(int x, int tl, int tr) {
    if (tl == tr) {
        t[x][0] = 1;
        return;
    }
    int tm = (tl + tr) / 2;
    build(2 * x, tl, tm);
    build(2 * x + 1, tm + 1, tr);
    t[x][0] = t[2 * x][0] + t[2 * x + 1][0];
}

void push(int x) {
    if (upd[x] == 0) {
        return;
    }
    upd[2 * x] ^= 1;
    upd[2 * x + 1] ^= 1;
    upd[x] = 0;
    swap(t[2 * x][0], t[2 * x][1]);
    swap(t[2 * x + 1][0], t[2 * x + 1][1]);
}

void update(int x, int tl, int tr, int l, int r) {
    if (r < tl || l > tr)
        return;
    if (l <= tl && r >= tr) {
        upd[x] ^= 1;
        res -= t[x][1];
        swap(t[x][0], t[x][1]);
        res += t[x][1];
        return;
    }
    int tm = (tl + tr) / 2;
    push(x);
    update(2 * x, tl, tm, l, r);
    update(2 * x + 1, tm + 1, tr, l, r);
    t[x][0] = t[2 * x][0] + t[2 * x + 1][0];
    t[x][1] = t[2 * x][1] + t[2 * x + 1][1];
}

void update(int x) {
    if (x == 0)
        return;
    // cout << "update " << st[x] << " " << x << "\n";
    update(1, 1, tt, tin[st[x]], tin[x]);
    update(p[st[x]]);
    // cout << "new: " << res << "\n";
}

void dfs(int x, int p) {
    ::p[x] = p;
    c[x] = (v[x].size() == 1);
    sz[x] = 1;
    k += c[x];
    for (auto to : v[x]) {
        if (to == p)
            continue;
        dfs(to, x);
        sz[x] += sz[to];
        c[x] += c[to];
    }
    // res += (x == root ? 0 : c[x] ^ 1);
}

void solve() {
    cin >> n >> q;
    for (int i = 0; i < n - 1; i++) {
        int a, b;
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    for (int i = 1; i <= n; i++) {
        if (v[i].size() > 1) {
            root = i;
            break;
        }
    }
    // cout << root << "\n";
    dfs(root, 0);
    st[root] = root;
    trace(root, 0);
    build(1, 1, tt);
    for (int i = 1; i <= n; i++) {
        if (c[i] % 2 == 0) {
            // cout << "i: " << c[i] << "\n";
            update(1, 1, tt, tin[i], tin[i]);
        }
    }
    // cout << res << "\n";
    // cout << "kerima\n";
    // return;
    while (q--) {
        int d;
        cin >> d;
        vector<int> g(d);
        for (auto &i : g) {
            cin >> i;
            k++;
            f[i]++;
            if (v[i].size() + f[i] == 2) {
                k--;
                continue;
            }
            update(i);
        }
        // cout << "Res: " << res << "\n";
        cout << (k % 2 ? -1 : res + n - 2 + d) << "\n";
        for (auto &i : g) {
            f[i]--;
            k--;
            if (v[i].size() + f[i] == 1) {
                k++;
                continue;
            }
            update(i);
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    // debugMode();
    int $ = 1;
    // cin >> $;
    while ($--) {
        solve();
    }
}

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 17 / 17
• Subtask 7: 30 / 30