#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define fi first
#define se second
const int MX = 5e5 + 10;
const int LG = 20;
const int INF = 1e9 + 7;
int N, K, dep[MX], sp[MX][LG];
vector<int> adj[MX];
vector<pii> s;
void dfs(int u, int v){
dep[u] = dep[v] + 1;
sp[u][0] = v;
for(int nxt : adj[u]){
if(nxt == v) continue;
dfs(nxt, u);
}
}
int dt[MX];
bool used[MX];
void bfs(){
for(int i = 0; i < MX; i++) dt[i] = INF;
queue<pii> q;
for(pii x : s){
dt[x.se] = 0;
q.push({0, x.se});
}
while(!q.empty()){
int cd = q.front().fi, cr = q.front().se;
q.pop();
for(int nxt : adj[cr]){
if(dt[nxt] > cd + 1){
dt[nxt] = cd + 1;
q.push({dt[nxt], nxt});
}
}
}
}
void mark(int u, int ndist){
if(dt[u] == ndist) used[nxt] = 1;
else return;
for(int nxt : adj[u]){
if(used[nxt]) continue;
mark(nxt, ndist - 1);
}
}
int main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> N >> K;
for(int i = 1; i < N; i++){
int u, v; cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
dfs(1, 0);
for(int i = 1; i <= K; i++){
int u; cin >> u;
s.push_back({dep[u], u});
}
for(int k = 1; k < LG; k++){
for(int i = 1; i <= N; i++){
sp[i][k] = sp[sp[i][k - 1]][k - 1];
}
}
sort(s.begin(), s.end(), greater<pii>());
bfs();
vector<int> ans;
for(int i = 0; i < K; i++){
int u = s[i].se, dist = 0;
for(int k = LG - 1; k >= 0; k--){
if(sp[u][k] != 0 && dt[sp[u][k]] == (dist + (1 << k))) u = sp[u][k], dist += 1 << k;
}
if(!used[u]){
ans.push_back(u);
mark(u, dt[u]);
}
}
cout << ans.size() << '\n';
for(int x : ans) cout << x << " ";
cout << '\n';
}
Compilation message
pastiri.cpp: In function 'void mark(int, int)':
pastiri.cpp:56:26: error: 'nxt' was not declared in this scope
56 | if(dt[u] == ndist) used[nxt] = 1;
| ^~~
