#ifndef Local
#pragma GCC optimize("O3,unroll-loops")
const int lim=1e5+100;
#else
const int lim=1e5+3;
#endif
const int lglim=17;
#include "bits/stdc++.h"
using namespace std;
//#define int int64_t
#define pb push_back
const int mod=998244353;
//const int mod=(1ll<<61)-1;
using pii=pair<int,int>;
struct inpout{
static const int sz=1<<15;
char inp[sz];
int curc=0,len=0;
inline char gc(){
if(curc==len){
len=(int)fread(inp,1,sz,stdin);
curc=0;
if(!len)return -1;
}
return inp[curc++];
}
inline void readstr(char*c,int ll){
for(int i=0;i<ll;i++){
c[i]=gc();
}
gc();
}
inline int readuint(){
int ans=0;
char c=gc();
while('0'<=c&&c<='9'){
ans=10*ans+c-'0';
c=gc();
}
return ans;
}
inline int readint(){
char c=gc();
bool isneg=(c=='-');
int ans=0;
if(!isneg)ans=c-'0';
c=gc();
while('0'<=c&&c<='9'){
ans=10*ans+c-'0';
c=gc();
}
if(isneg)return -ans;
return ans;
}
char out[sz];
int curind=0;
inline void flush(){
fwrite(out,1,curind,stdout);
curind=0;
}
inline void putchar(char c){
out[curind++]=c;
if(curind==sz)flush();
}
char temp[10];
inline void putint(int i){
if(i<0){
putchar('-');
i=-i;
}
int lll=0;
while(i){
temp[lll++]=(i%10)+'0';
i/=10;
}
while(lll){
putchar(temp[--lll]);
}
putchar('\n');
}
}io;
int n,m,k;
int tin[lim],dep[lim],tt=0;
int lift[lglim][lim];
vector<pii>v[lim];
int pare[lim];
inline void tour(int node,int par){
tin[node]=tt++;
dep[node]=dep[par]-1;
lift[0][node]=par;
for(int i=1;i<lglim;i++){
if(!lift[i][node]=lift[i-1][lift[i-1][node]])break;
}
for(auto [j,c]:v[node]){
if(j^par){
pare[j]=c;
tour(j,node);
}
}
}
int lgll[lim];
inline int lca(int x,int y){
if(dep[y]<dep[x])swap(x,y);
int dif=dep[y]-dep[x];
while(dif){
int lll=lgll[dif&-dif];
dif-=1<<lll;
x=lift[lll][x];
}
if(x==y)return x;
for(int i=lgll[-dep[x]];0<=i;i--){
if(lift[i][x]^lift[i][y]){
x=lift[i][x];
y=lift[i][y];
}
}
return lift[0][x];
}
int val[lim];
bool can[lim];
vector<int>ans;
inline int dfs(int node,int par){
for(auto [j,c]:v[node]){
if(j^par){
val[node]+=dfs(j,node);
}
}
if(2*k<=val[node]){
can[pare[node]]=1;
}
return val[node];
}
inline void solve(){
lgll[1]=0;
for(int i=2;i<lim;i++){
lgll[i]=lgll[i/2]+1;
}
n=io.readuint(),m=io.readuint(),k=io.readuint();
for(int i=1;i<=n-1;i++){
int x=io.readuint(),y=io.readuint();
v[x].pb({y,i});
v[y].pb({x,i});
}
tour(1,0);
int inds[n+1];
for(int r=0;r<m;r++){
int s;
s=io.readuint();
for(int i=0;i<s;i++){
inds[i]=io.readuint();
}
sort(inds,inds+s,[&](int i,int j) -> bool {
return tin[i]<tin[j];
});
inds[s]=inds[0];
for(int i=0;i<s;i++){
val[inds[i]]++;
val[inds[i+1]]++;
val[lca(inds[i],inds[i+1])]-=2;
}
}
dfs(1,0);
int cnt=0;
for(int i=0;i<n;i++){
if(can[i])cnt++;
}
cout<<cnt<<"\n";
for(int i=0;i<n;i++)if(can[i])cout<<i<<" ";
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
#ifdef Local
freopen(".in","r",stdin);
freopen(".out","w",stdout);
#else
#endif
int t=1;
//cin>>t;
while (t--)
{
solve();
}
}
Compilation message
railway.cpp: In function 'void tour(int, int)':
railway.cpp:100:12: error: lvalue required as left operand of assignment
100 | if(!lift[i][node]=lift[i-1][lift[i-1][node]])break;
| ^~~~~~~~~~~~~~
