Submission #876695

#	Time	Username	Problem	Language	Result	Execution time	Memory
876695		serkanrashid	Jail (JOI22_jail)	C++14	49 / 100	5047 ms	12880 KiB

jail

#include <bits/stdc++.h>
#define endl "\n"

using namespace std;

const int maxn = 12*1e4+5;

int q,n,m;
vector<int>g[maxn],v[maxn];
int s[maxn],t[maxn];
int used[maxn];
bool ans;
int kr,prechki;

void precom()
{
    for(int i=1;i<=n;i++)
    {
        g[i].clear();
        used[i] = 0;
        v[i].clear();
    }
}

void read()
{
    cin >> n;
    precom();
    int a,b;
    for(int i=1;i<n;i++)
    {
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    cin >> m;
    for(int i=1;i<=m;i++)
    {
        cin >> s[i] >> t[i];
    }
}

void dfs(int beg)
{
    used[beg] = 1;
    for(int nb:v[beg])
    {
        if(used[nb]==1) ans = false;
        if(!used[nb]) dfs(nb);
    }
    used[beg] = 2;
}

void dfskr(int beg, int par, int sum)
{
    sum += used[beg];
    if(beg==kr) prechki = sum;
    for(int nb:g[beg])
    {
        if(nb!=par) dfskr(nb,beg,sum);
    }
}

void solve()
{
    /*for(int i=1;i<=n;i++)
    {
        cout << i << "->";
        for(int nb:g[i]) cout << " " << nb;
        cout << endl;
    }*/
    for(int i=1;i<=m;i++)
    {
        for(int j=i+1;j<=m;j++)
        {
            int ch1,ch2;
            ch1 = ch2 = 0;
            used[s[j]] = 2;
            used[t[j]] = 1;
            kr = t[i];
            dfskr(s[i],s[i],0);
            ch1 = prechki;
            used[s[j]] = 0;
            used[t[j]] = 0;
            if(ch1==3)
            {
                cout << "No" << endl;
                return;
            }
            used[s[i]] = 2;
            used[t[i]] = 1;
            kr = t[j];
            dfskr(s[j],s[j],0);
            ch2 = prechki;
            used[s[i]] = 0;
            used[t[i]] = 0;
            if(ch2==3)
            {
                cout << "No" << endl;
                return;
            }
            if(ch1==1||ch2==2) v[i].push_back(j);
            if(ch1==2||ch2==1) v[j].push_back(i);
        }
    }
    /*for(int i=1;i<=m;i++)
    {
        cout << i << "->";
        for(int nb:v[i]) cout << " " << nb;
        cout << endl;
    }*/
    ans = true;
    for(int i=1;i<=m;i++) used[i] = 0;
    for(int i=1;i<=m;i++)
    {
        if(!used[i]) dfs(i);
    }
    if(ans) cout << "Yes" << endl;
    else cout << "No" << endl;
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
	cin >> q;
	for(int i=1;i<=q;i++)
    {
        read();
        solve();
    }
return 0;
}
/*
1
8
1 2
2 3
3 4
4 5
5 6
6 7
7 8
4
1 5
2 6
3 7
4 8
*/

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