Submission #970351

#	Time	Username	Problem	Language	Result	Execution time	Memory
970351		zwezdinv	Jail (JOI22_jail)	C++17	0 / 100	25 ms	62040 KiB

jail

#include<bits/stdc++.h>
using namespace std;

const int LG = 18;
const int N = 1.2e5;

int n;
int bp[LG][N];
vector<int> g[N * LG];
vector<int> tr[N];
int tin[N], tout[N];
int tim = 0;
void build(int u, int p) {
    tin[u] = tim++;
    bp[0][u] = p;
    for (int k = 1; bp[k - 1][u] != -1; ++k) {
        bp[k][u] = bp[k - 1][bp[k - 1][u]];
        g[u + n * k].push_back(u + n * (k - 1));
        g[u + n * k].push_back(bp[k - 1][u] + n * (k - 1));
    }
    for (auto to: tr[u]) {
        if (to != p) build(to, u);
    }
    tout[u] = tim++;
}
bool is_par(int u, int v) {
    return tin[u] <= tin[v] && tout[v] <= tout[u];
}

int used[N * LG];
bool dfs(int u) {
    bool ok = true;
    used[u] = 1;
    for (auto to : g[u]) {
//        cout << u << ' ' << to << endl;
        if (!used[to]) ok &= dfs(to);
        else if (used[to] == 1) ok = false;
    }
    used[u] = 2;
    return ok;
}

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    int tests;
    cin >> tests;
    while (tests--) {
        cin >> n;
        for (int i = 0; i < n; ++i) tr[i].clear();
        for (int i = 0; i < n; ++i) for (int j = 0; j < LG; ++j) bp[j][i] = -1;
        for (int i = 0; i < n - 1; ++i) {
            int u, v;
            cin >> u >> v;
            --u, --v;
            tr[u].push_back(v);
            tr[v].push_back(u);
        }
        build(0, -1);
        int m;
        cin >> m;
        for (int i = 0; i < n * LG + m; ++i) g[i].clear(), used[i] = 0;
        for (int i = 0; i < m; ++i) {
            int s, t;
            cin >> s >> t;
            --s, --t;
            g[t].push_back(i + n * LG);
            if (is_par(t, s)) {
                for (int k = LG - 1; k >= 0; --k) {
                    if (bp[k][s] != -1 && !is_par(bp[k][s], t)) {
                        g[i + n * LG].push_back(s + n * k);
                        s = bp[k][s];
                    }
                }
            } else {
                t = bp[0][t];
                if (s == t) {
                    g[i + n * LG].push_back(s);
                } else {
                    if (tin[s] < tin[t]) swap(s, t);
                    for (int k = LG - 1; k >= 0; --k) {
                        if (bp[k][s] != -1 && !is_par(bp[k][s], t)) {
                            g[i + n * LG].push_back(s + n * k);
                            s = bp[k][s];
                        }
                        if (bp[k][t] != -1 && !is_par(bp[k][t], s)) {
                            g[i + n * LG].push_back(t + n * k);
                            t = bp[k][t];
                        }
                    }
//                    cout << s << ' ' << t << endl;
                    g[i + n * LG].push_back(s);
                    s = bp[0][s];
//                    cout << s << ' ' << t << endl;
                    g[i + n * LG].push_back(s);
                    if (t != s) g[i + n * LG].push_back(t);
                }
            }
        }
        bool ans = true;
        for (int i = 0; i < n * LG + m; ++i) if (!used[i]) ans &= dfs(i);
        cout << (ans ? "Yes\n" : "No\n");
    }
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 16
• Subtask 4: 0 / 28
• Subtask 5: 0 / 12
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23