| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 786292 | chanhchuong123 | Railway (BOI17_railway) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
#define task ""
#define fi first
#define se second
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (b), _a = (a); i >= _a; --i)
template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
if (a < b) {a = b; return true;} return false;
}
const int dx[] = {-1, 0, 0, +1};
const int dy[] = {0, -1, +1, 0};
const int MAX = 100100;
int n, k, m;
int ID[MAX];
vector<int> res;
set<int> add[MAX];
vector<int> del[MAX];
int h[MAX], anc[17][MAX];
vector<pair<int, int>> adj[MAX];
void dfs(int u, int p) {
for (pair<int, int> &x: adj[u]) if (x.fi != p) {
int v = x.fi;
ID[v] = x.se;
anc[0][v] = u;
h[v] = h[u] + 1;
for (int j = 1; j <= 16; ++j) {
anc[j][v] = anc[j - 1][anc[j - 1][v]];
}
dfs(v, u);
}
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u, v);
int k = h[u] - h[v];
for (int j = 0; (1 << j) <= k; ++j) {
if (k >> j & 1) u = anc[j][u];
}
if (u == v) return u;
for (int j = 16; j >= 0; --j) {
if (anc[j][u] != anc[j][v]) {
u = anc[j][u];
v = anc[j][v];
}
}
return anc[0][u];
}
void reDfs(int u, int p) {
for (pair<int, int> &x: adj[u]) if (x.fi != p) {
int v = x.fi; reDfs(v, u); if (add[u].size() < add[v].size()) add[u].swap(add[v]);
for (int x: add[v]) add[u].insert(x);
}
for (int &x: del[u]) add[u].erase(x);
if (add[u].size() >= k && u != 1) {
res.push_back(ID[u]);
}
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> n >> m >> k;
for (int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
}
dfs(1, -1);
for (int i = 1; i <= m; ++i) {
int s, c, u; cin >> s >> c;
--s; add[c].insert(i);
while (s--) {
cin >> u;
c = lca(c, u);
add[u].insert(i);
}
del[c].push_back(i);
}
reDfs(1, -1);
sort(all(res));
cout << res.size() << '\n';
for (int &x: res) cout << x << ' ';
return 0;
}