Submission #652709

#	Time	Username	Problem	Language	Result	Execution time	Memory
652709		kym	Pastiri (COI20_pastiri)	C++14	100 / 100	819 ms	130984 KiB

pastiri

#include <bits/stdc++.h>
using namespace std;
#define int ll 
#define FOR(i,s,e) for(ll i = s; i <= (ll)e; ++i)
#define DEC(i,s,e) for(ll i = s; i >= (ll)e; --i)
#define IAMSPEED ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef LOCAL
#define db(x) cerr << #x << "=" << x << "\n"
#define db2(x, y) cerr << #x << "=" << x << " , " << #y << "=" << y << "\n"
#define db3(a,b,c) cerr<<#a<<"="<<a<<","<<#b<<"="<<b<<","<<#c<<"="<<c<<"\n"
#define dbv(v) cerr << #v << ":"; for (auto ite : v) cerr << ite << ' '; cerr <<"\n"
#define dbvp(v) cerr << #v << ":"; for (auto ite : v) cerr << "{"  << ite.f << ',' << ite.s << "} "; cerr << "\n"
#define dba(a,ss,ee) cerr << #a << ":"; FOR(ite,ss,ee) cerr << a[ite] << ' '; cerr << "\n"
#else
#define db(x)
#define db2(x,y)
#define db3(a,b,c)
#define dbv(v)
#define dbvp(v)
#define dba(a,ss,ee)
#endif
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define ll long long 
#define pb push_back
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define f first 	
#define s second
#define g0(x) get<0>(x)
#define g1(x) get<1>(x)
#define g2(x) get<2>(x)
#define g3(x) get<3>(x)
#define reach cerr << "LINE: " << __LINE__ << "\n";
typedef pair <ll, ll> pi;
typedef tuple<ll,ll,ll> ti3;
typedef tuple<ll,ll,ll,ll> ti4;
ll rand(ll a, ll b) { return a + rng() % (b-a+1); }
const int MOD = 1e9 + 7;
const int inf = (int)1e9 + 500;
const long long oo = (ll)1e18 + 500;
template <typename T> bool chmax(T& a, const T b) { return a<b ? a = b, 1 : 0; }
template <typename T> bool chmin(T& a, const T b) { return a>b ? a = b, 1 : 0; }
const int MAXN = 500005;
int n,k;
vector<int> V[MAXN];
vector<int> sheeps;
set<int> level[MAXN];
int depth[MAXN];
int twok[MAXN][1];
int st[MAXN], en[MAXN];
int cnt=1;
int rev[MAXN];

void dfs(int x, int p) {
	st[x]=cnt;
	rev[cnt]=x;
	++cnt;
	twok[x][0]=p;
	for(auto v:V[x])if(v!=p) {
		depth[v]=depth[x]+1;
		dfs(v,x);
	}
	en[x]=cnt-1;
}
int dist[MAXN];
set<pi,greater<pi>> s;
vector<int>out;
bool vis[MAXN];
bool is[MAXN];
void clearr(int x) {
	
	if(vis[x])return;
	vis[x]=1;
	for(auto v:V[x]){
		if(vis[v])continue;
		if(dist[x]==dist[v]+1)clearr(v);
	}
}

int32_t main() 
{
	IAMSPEED
	cin >> n >> k;
	FOR(i,1,n-1) {
		int a,b; cin >> a >> b;
		V[a].pb(b);
		V[b].pb(a);
	}
	FOR(i,1,k) {
		int x; cin >> x;
		is[x]=1;
		sheeps.pb(x);
	}
	dfs(1,-1);
	for(auto i:sheeps) {
		s.insert(pi(depth[i],i));
	}
	queue<int> q;
	FOR(i,0,MAXN-1)dist[i]=oo;
	for(auto i:sheeps){
		q.push(i);
		dist[i]=0;
	}
	while(q.size()) {
		int x=q.front(); 
		q.pop();
		for(auto v:V[x]){
			if(dist[v] > dist[x]+1) {
				dist[v]=dist[x]+1;
				q.push(v);
			}
		}
	}
	for(auto sheep:s){
		int x=sheep.s; int dd=sheep.f;
		if(vis[x])continue;
		int node=x;
		while(node != 1 && (dist[twok[node][0]] == depth[x] - depth[twok[node][0]]))node=twok[node][0];
		out.pb(node);
		clearr(node);
	}
	cout << out.size() << '\n';
	for(auto i:out)cout << i << ' ' ;
}

Compilation message (stderr)

pastiri.cpp: In function 'int32_t main()':
pastiri.cpp:116:22: warning: unused variable 'dd' [-Wunused-variable]
  116 |   int x=sheep.s; int dd=sheep.f;
      |                      ^~

• Subtask 1: 8 / 8
• Subtask 2: 18 / 18
• Subtask 3: 23 / 23
• Subtask 4: 51 / 51