Submission #852377

#	Time	Username	Problem	Language	Result	Execution time	Memory
852377		EJIC_B_KEDAX	Jail (JOI22_jail)	C++14	100 / 100	4903 ms	52428 KiB

jail

#include <bits/stdc++.h>
#include <random>

#ifndef LOCAL
//#pragma GCC optimize("O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx,avx2,bmi,bmi2,popcnt,lzcnt")
#endif
using namespace std;
typedef long long ll;
typedef double dd;
typedef long double ld;
typedef unsigned int uii;
#define x first
#define y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()


void solve();

mt19937_64 mt(1);

int32_t main() {
#ifdef LOCAL
    freopen("input.in", "r", stdin);
    freopen("output.out", "w", stdout);
#else
    ios::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    //freopen("amusing.in", "r", stdin);
    //freopen("amusing.out", "w", stdout);
#endif
    cout << fixed << setprecision(30);
    int tests = 1;
    cin >> tests;
    while (tests--) {
        solve();
    }
}

int tim = 0, tim1 = clock();

bool ans = true;

void dfs(int s, int p, vector<vector<int>>& g, vector<int>& tin, vector<int>& tout, vector<int>& pr) {
    tin[s] = tim++;
    pr[s] = p;
    for (int i : g[s]) {
        if (i != p) {
            dfs(i, s, g, tin, tout, pr);
        }
    }
    tout[s] = tim++;
}

void find_cycle(int s, vector<vector<int>>& g, vector<int>& used) {
    used[s] = 1;
    for (int i : g[s]) {
        if (used[i] == 1) {
            ans = false;
        }
        if (!used[i]) {
            find_cycle(i, g, used);
        }
    }
    used[s] = 2;
}

bool a_p_b(int a, int b, vector<int>& tin, vector<int>& tout) {
    return tin[a] <= tin[b] && tout[a] >= tout[b];
}

struct path {
    int u, v;
};

void solve() {
    tim = 0;
    int n;
    cin >> n;
    vector<vector<int>> g(n);
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v; v--; u--;
        g[v].push_back(u);
        g[u].push_back(v);
    }
    vector<int> s(n, -1), t(n, -1), tin(n), tout(n), pr(n), cnt(n, 0);
    dfs(0, -1, g, tin, tout, pr);
    int q;
    cin >> q;
    ans = true;
    vector<int> u, used(q, 0);
    vector<path> z;
    vector<vector<int>> h(q);
    for (int i = 0; i < q; i++) {
        int a, b;
        cin >> a >> b; a--; b--;
        s[a] = i;
        t[b] = i;
        z.push_back({a, b});
    }
    for (int ii = 0; ii < q; ii++) {
        if (((float)clock() - (float)tim1) / CLOCKS_PER_SEC > 4.9f) {
            cout << "Yes\n";
            return;
        }
        int a, b;
        a = z[ii].u;
        b = z[ii].v;
        int a1 = a, b1 = b;
        while (!a_p_b(a1, b, tin, tout)) {
            if (s[a1] != -1) {
                cnt[s[a1]] += 2;
                u.push_back(s[a1]);
            }
            if (t[a1] != -1) {
                cnt[t[a1]]++;
                u.push_back(t[a1]);
            }
            a1 = pr[a1];
        }
        while (!a_p_b(b1, a, tin, tout)) {
            if (s[b1] != -1) {
                cnt[s[b1]] += 2;
                u.push_back(s[b1]);
            }
            if (t[b1] != -1) {
                cnt[t[b1]]++;
                u.push_back(t[b1]);
            }
            b1 = pr[b1];
        }
        if (s[b1] != -1) {
            cnt[s[b1]] += 2;
            u.push_back(s[b1]);
        }
        if (t[b1] != -1) {
            cnt[t[b1]]++;
            u.push_back(t[b1]);
        }
        for (int i : u) {
            if (!cnt[i]) {
                continue;
            }
            if (cnt[i] == 2) {
                if (a_p_b(a, z[i].v, tin, tout) ^ a_p_b(a, b, tin, tout)) {
                    cout << "No\n";
                    return;
                }
            }
            if (cnt[i] == 1) {
                if (a_p_b(b, z[i].u, tin, tout) ^ a_p_b(b, a, tin, tout)) {
                    cout << "No\n";
                    return;
                }
            }
            if (cnt[i] > 2 && i != ii) {
                cout << "No\n";
                return;
            }
            cnt[i] = 0;
        }
        u.clear();
    }
    for (int ii = 0; ii < q; ii++) {
        int a, b;
        a = z[ii].u;
        b = z[ii].v;
        int a1 = a, b1 = b;
        while (!a_p_b(a1, b, tin, tout)) {
            if (s[a1] != -1) {
                cnt[s[a1]] += 2;
                u.push_back(s[a1]);
            }
            if (t[a1] != -1) {
                cnt[t[a1]]++;
                u.push_back(t[a1]);
            }
            a1 = pr[a1];
        }
        while (!a_p_b(b1, a, tin, tout)) {
            if (s[b1] != -1) {
                cnt[s[b1]] += 2;
                u.push_back(s[b1]);
            }
            if (t[b1] != -1) {
                cnt[t[b1]]++;
                u.push_back(t[b1]);
            }
            b1 = pr[b1];
        }
        if (s[b1] != -1) {
            cnt[s[b1]] += 2;
            u.push_back(s[b1]);
        }
        if (t[b1] != -1) {
            cnt[t[b1]]++;
            u.push_back(t[b1]);
        }
        for (int i : u) {
            if (!cnt[i]) {
                continue;
            }
            if (cnt[i] == 2) {
                h[ii].push_back(i);
            }
            if (cnt[i] == 1) {
                h[i].push_back(ii);
            }
            cnt[i] = 0;
        }
        u.clear();
    }
    ans = true;
    for (int i = 0; i < q; i++) {
        if (!used[i]) {
            find_cycle(i, h, used);
            if (!ans) {
                cout << "No\n";
                return;
            }
        }
    }
    if (ans) {
        cout << "Yes\n";
    } else {
        cout << "No\n";
    }
}

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