Submission #890816

#	Time	Username	Problem	Language	Result	Execution time	Memory
890816		vjudge1	Jail (JOI22_jail)	C++17	61 / 100	225 ms	32424 KiB

jail

#include <bits/stdc++.h>

using namespace std;

#define all(x) x.begin(), x.end()
#define ar array
#define pb push_back
#define ln '\n'
#define int long long

using i64 = long long;

template <class F, class _S>
bool chmin(F &u, const _S &v){
    bool flag = false;
    if ( u > v ){
        u = v; flag |= true;
    }
    return flag;
}

template <class F, class _S>
bool chmax(F &u, const _S &v){
    bool flag = false;
    if ( u < v ){
        u = v; flag |= true;
    }
    return flag;
}

void solve(){
    int n; cin >> n;
    vector <vector<int>> G(n);
    bool Qflag = true;
    for ( int i = 0; i + 1 < n; i++ ){
        int u, v; cin >> u >> v;
        --u, --v;
        G[u].pb(v), G[v].pb(u);
        Qflag &= (u + 1 == v);
    }
    int m; cin >> m;
    vector <int> S(m), T(m);
    for ( int i = 0; i < m; i++ ){
        cin >> S[i] >> T[i];
        --S[i], --T[i];
    }
    if ( Qflag ){
        vector <int> pf(n + 1);
        vector <ar<int,2>> A;
        for ( int i = 0; i < m; i++ ){
            if ( S[i] > T[i] ){
                pf[T[i]]++;
                pf[S[i] + 1]--;
            }
            A.pb({min(S[i], T[i]), max(S[i], T[i])});
        }
        for ( int i = 1; i < n; i++ ){
            pf[i] += pf[i - 1];
        }
        for ( int i = 0; i < m; i++ ){
            if ( S[i] < T[i] ){
                int s = pf[T[i]] - (S[i] ? pf[S[i] - 1] : 0);
                if ( s ){
                    cout << "No\n";
                    return;
                }
            }
        }
        sort(all(A));
        int mx = -1;
        for ( auto &[l, r]: A ){
            if ( mx >= r ){
                cout << "No\n";
                return;
            } chmax(mx, r);
        }
        cout << "Yes\n"; return;
    }
    vector <vector<int>> up(20, vector <int> (n));
    vector <int> d(n), tin(n), tout(n);
    int timer = 0;
    auto dfs = [&](auto dfs, int u, int p) -> void{
        up[0][u] = p;
        for ( int i = 1; i < 20; i++ ){
            up[i][u] = up[i - 1][up[i - 1][u]];
        }
        tin[u] = ++timer;
        for ( auto &v: G[u] ){
            if ( v != p ){
                d[v] = d[u] + 1;
                dfs(dfs, v, u);
            }
        } tout[u] = timer;
    };
    dfs(dfs, 0, 0);
    auto lca = [&](int u, int v){
        if ( d[u] < d[v] ) swap(u, v);
        int df = d[u] - d[v];
        for ( int i = 0; i < 20; i++ ){
            if ( df >> i & 1 ){
                u = up[i][u];
            }
        }
        if ( u == v ){
            return u;
        }
        for ( int i = 19; i >= 0; i-- ){
            if ( up[i][u] != up[i][v] ){
                u = up[i][u];
                v = up[i][v];
            }
        }
        return up[0][u];
    };
    auto isPar = [&](int u, int v){
        return tin[u] <= tin[v] && tout[u] >= tout[v];
    };
    auto onPath = [&](int u, int x, int v){
        return (isPar(x, u) || isPar(x, v)) && isPar(lca(u, v), x);
    };
    auto bad = [&](int j, int i){
        return onPath(S[i], S[j], T[i]) || onPath(S[j], T[i], T[j]);
    };
    vector <vector<int>> P(m);
    for ( int i = 0; i < m; i++ ){
        for ( int j = i + 1; j < m; j++ ){
            if ( bad(i, j) ){
                P[i].pb(j);
            }
            if ( bad(j, i) ){
                P[j].pb(i);
            }
        }
    }
    vector <int> us(m);
    auto dfs2 = [&](auto dfs2, int u) -> bool{
        us[u] = 1;
        for ( auto &v: P[u] ){
            if ( !us[v] ){
                if ( !dfs2(dfs2, v) ){
                    return false;
                }
            } else if ( us[v] == 1 ){
                return false;
            }
        }
        us[u] = 2;
        return true;
    };
    bool flag = true;
    for ( int i = 0; i < m; i++ ){
        if ( !us[i] ){
            flag &= dfs2(dfs2, i);
        }
    }
    cout << (flag ? "Yes\n" : "No\n");
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int t; cin >> t;
    while ( t-- ){
        solve();
    }

    cout << '\n';
}

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