#include<bits/stdc++.h>
using namespace std;
#define task "a"
#define ll long long
#define fi first
#define se second
#define ii pair<ll, ll>
const int mxN = 12e4 + 7;
int n, in[3000007], h[mxN], par[mxN][25], id[mxN][25][2], num;
vector<int> topo[3000007], w[mxN];
void Add(int u, int v)
{
topo[u].push_back(v);
in[v]++;
}
void DFS(int j)
{
id[j][0][0] = ++num;
id[j][0][1] = ++num;
for (int i = 1; i <= __lg(h[j]); i++)
{
par[j][i] = par[par[j][i - 1]][i - 1];
id[j][i][0] = ++num;
id[j][i][1] = ++num;
Add(id[j][i][0], id[j][i - 1][0]);
Add(id[j][i][0], id[par[j][i - 1]][i - 1][0]);
Add(id[j][i - 1][1], id[j][i][1]);
Add(id[par[j][i - 1]][i - 1][1], id[j][i][1]);
}
for (int i : w[j])
{
if (h[i])
continue;
h[i] = h[j] + 1;
par[i][0] = j;
DFS(i);
}
}
int LCA(int u, int v)
{
if (h[u] < h[v])
swap(u, v);
for (int i = 20; i >= 0; i--)
{
if (h[par[u][i]] >= h[v])
u = par[u][i];
}
if (u == v)
return u;
for (int i = 20; i >= 0; i--)
{
if (par[u][i] != par[v][i])
{
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void Walk(int j, int u, int root, int tt)
{
for (int i = 20; i >= 0; i--)
{
if (h[u] < (1 << i))
continue;
if (h[par[u][i]] + 1 < root)
continue;
if (!tt)
Add(j, id[u][i][0]);
else
Add(id[u][i][1], j);
u = par[u][i];
}
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie();
//freopen(task".INP", "r", stdin);
//freopen(task".OUT", "w", stdout);
int tst;
cin >> tst;
while (tst--)
{
cin >> n;
num = 0;
for (int i = 1; i <= n; i++)
{
h[i] = 0;
w[i].clear();
}
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
w[u].push_back(v);
w[v].push_back(u);
}
h[1] = 1;
DFS(1);
int m;
cin >> m;
for (int i = 1; i <= m; i++)
{
int u, v;
cin >> u >> v;
num++;
Add(id[u][0][0], num);
Add(num, id[v][0][1]);
int root = LCA(u, v);
Walk(num, par[u][0], h[root], 0);
Walk(num, v, h[root] + 1, 0);
Walk(num, par[v][0], h[root], 1);
Walk(num, u, h[root] + 1, 1);
//cout << num << " " << root << '\n';
}
// for (int i = 1; i <= num; i++)
// {
// cout << i << " : ";
// for (int j : topo[i])
// cout << j << " ";
// cout << '\n';
// }
queue<int> q;
for (int i = 1; i <= num; i++)
{
if (!in[i])
q.push(i);
}
int cnt = 0;
while (q.size())
{
int j = q.front();
q.pop();
cnt++;
for (int i : topo[j])
{
--in[i];
if (!in[i])
q.push(i);
}
}
if (cnt != num)
cout << "No\n";
else
cout << "Yes\n";
for (int i = 1; i <= num; i++)
{
in[i] = 0;
topo[i].clear();
}
}
}
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |