Submission #890776

#	Time	Username	Problem	Language	Result	Execution time	Memory
890776		vjudge1	Jail (JOI22_jail)	C++17	21 / 100	5093 ms	1116 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);
    for ( int i = 0; i + 1 < n; i++ ){
        int u, v; cin >> u >> v;
        --u, --v;
        G[u].pb(v), G[v].pb(u);
    }
    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];
    }
    vector <int> tmp;
    auto dfs = [&](auto dfs, int u, int p, int des) -> bool{
        if ( u == des ){
            return true;
        }
        for ( auto &v: G[u] ){
            if ( v != p ){
                if ( dfs(dfs, v, u, des) ){
                    tmp.pb(u);
                    return true;
                }
            }
        }
        return false;
    };
    vector <vector<int>> lst(m);
    for ( int i = 0; i < m; i++ ){
        tmp.clear();
        dfs(dfs, S[i], -1, T[i]);
        reverse(all(tmp));
        tmp.pb(T[i]);
        lst[i] = tmp;
    }
    vector <int> p(m);
    iota(all(p), 0);
    do{
        vector <int> us(n);
        for ( int i = 0; i < m; i++ ){
            us[S[i]] = true;
        }
        bool good = true;
        for ( int i = 0; i < m; i++ ){
            auto &tmp = lst[p[i]];
            int pre = S[p[i]];
            for ( int j = 1; j < tmp.size(); j++ ){
                if ( us[tmp[j]] ){
                    good = false;
                } us[pre] = false;
                us[pre = tmp[j]] = true;
            }
        }
        if ( good ){
            cout << "Yes\n";
            return;
        }
    } while ( next_permutation(all(p)) );
    cout << "No\n";
}

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

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

    cout << '\n';
}

Compilation message (stderr)

jail.cpp: In function 'void solve()':
jail.cpp:79:32: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |             for ( int j = 1; j < tmp.size(); j++ ){
      |                              ~~^~~~~~~~~~~~

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