Submission #927291

#	Time	Username	Problem	Language	Result	Execution time	Memory
927291		andrei_boaca	Jail (JOI22_jail)	C++17	0 / 100	3 ms	18780 KiB

jail

#include <bits/stdc++.h>

using namespace std;
int t,n,m,A[120005],B[120005],in[120005],out[120005],timp,par[120005],niv[1200005],dp[21][120005];
vector<int> muchii[120005];
vector<int> edges[120005];
bool isancestor(int a,int b)
{
    return in[a]<=in[b]&&out[a]>=out[b];
}
int LCA(int a,int b)
{
    if(niv[a]>niv[b])
        swap(a,b);
    if(isancestor(a,b))
        return a;
    for(int i=18;i>=0;i--)
        if(dp[i][a]!=0&&!isancestor(dp[i][a],b))
            a=dp[i][a];
    return par[a];
}
int dist(int a,int b)
{
    int lca=LCA(a,b);
    return niv[a]+niv[b]-2*niv[lca];
}
void dfs(int nod)
{
    timp++;
    in[nod]=timp;
    dp[0][nod]=par[nod];
    for(int i=1;i<=18;i++)
        dp[i][nod]=dp[i-1][dp[i-1][nod]];
    for(int i:muchii[nod])
        if(i!=par[nod])
        {
            par[i]=nod;
            niv[i]=niv[nod]+1;
            dfs(i);
        }
    out[nod]=timp;
}
int grad[120005];
void solve()
{
    cin>>n;
    timp=0;
    for(int i=1;i<=n;i++)
        muchii[i].clear();
    for(int i=1;i<n;i++)
    {
        int a,b;
        cin>>a>>b;
        muchii[a].push_back(b);
        muchii[b].push_back(a);
    }
    dfs(1);
    cin>>m;
    for(int i=1;i<=m;i++)
    {
        cin>>A[i]>>B[i];
        edges[i].clear();
        grad[i]=0;
    }
    for(int i=1;i<=m;i++)
        for(int j=i+1;j<=m;j++)
            if(i!=j)
            {
                if(dist(A[i],A[j])+dist(A[j],B[i])==dist(A[i],B[i]))
                {
                    edges[j].push_back(i);
                    grad[i]++;
                }
                if(dist(A[i],B[j])+dist(B[j],B[i])==dist(A[i],B[i]))
                {
                    edges[i].push_back(j);
                    grad[j]++;
                }
            }
    queue<int> coada;
    int cnt=0;
    for(int i=1;i<=m;i++)
        if(grad[i]==0)
            coada.push(i);
    while(!coada.empty())
    {
        int nod=coada.front();
        coada.pop();
        cnt++;
        for(int i:edges[nod])
        {
            grad[i]--;
            if(grad[i]==0)
                coada.push(i);
        }
    }
    if(cnt==m)
        cout<<"Yes\n";
    else
        cout<<"No\n";
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin>>t;
    while(t--)
        solve();
    return 0;
}

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