Submission #994293

#	Time	Username	Problem	Language	Result	Execution time	Memory
994293		vjudge1	Jail (JOI22_jail)	C++17	60 / 100	464 ms	1048576 KiB

jail

#include <bits/stdc++.h>
using namespace std;
vector<vector<int> > g, g2;
vector<int> vis;
vector<int> path;
vector<vector<int> > p;
void dfs(int v, int pa)
{

    path.push_back(v);
    p[v] = path;
    for(auto x : g[v])
    {
        if(x != pa) dfs(x, v);
    }
    path.pop_back();
}
bool c(int v)
{

    vis[v] = 1;
    for(auto x : g2[v])
    {
        //cout << v << " " << x << endl;
        if(vis[x] == 1) return 1;
        if(vis[x] == 0) if(c(x)) return 1;
    }
    vis[v] = 2;
    return 0;
}
void solve()
{
    int n, m;
    cin >> n;
    g.assign(n + 1, {});
    vis.assign(n + 1, 0);
    p.assign(n + 1, {});
    for(int i = 0; i < n - 1; i++)
    {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    cin >> m;
    g2.assign(m + 1, {});
    vector<int> a(m), b(m);
    for(int i = 0; i < m; i++) cin >> a[i] >> b[i];
    dfs(1, 0);
    //return;
    vector<vector<int> > inc(n + 1);
    for(int i = 0; i < m; i++)
    {
        vector<int> fi = p[a[i]], se = p[b[i]];
        int y = fi.size(), z = se.size();
        int be = 0;
        while(be < y - 1 && be < z - 1)
        {
            if(fi[be + 1] == se[be + 1]) be++;
            else break;
        }
        for(int j = be; j < y; j++)
        {
            inc[fi[j]].push_back(i);
        }
        for(int j = be; j < z; j++)
        {
            inc[se[j]].push_back(i);
        }
    }
    for(int i = 0; i < m; i++)
    {
        for(auto x : inc[a[i]])
        {
            if(x != i) g2[x].push_back(i);
        }
        for(auto x : inc[b[i]])
        {

            if(x != i) g2[i].push_back(x);
        }
    }
    vis.assign(m + 1, 0);
    for(int i = 0; i < m; i++)
    {
        if(vis[i] == 0 && c(i))
        {
            cout << "No\n";
            return;
        }
    }
    cout << "Yes\n";
}
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int q;
    cin >> q;
    while(q--) solve();
}

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