Submission #867778

#	Time	Username	Problem	Language	Result	Execution time	Memory
867778		epicci23	Parkovi (COCI22_parkovi)	C++17	110 / 110	1350 ms	41292 KiB

Main

#include "bits/stdc++.h"
using namespace std;
#define pb push_back
#define endl "\n" 
#define int long long
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()

constexpr int N = 2e5 + 5;
constexpr int INF = 1e18;

int n,k;
vector<array<int,2>> v[N];
bool ok=1;
int vis[N];
int dp[N];
int depth[N];
int maxi[N];
int ck;

void dfs(int c,int p,int d){

  if(!ok) return;
  depth[c]=d;
  maxi[c]=d;

  for(array<int,2> x:v[c]){
  	int u=x[0],co=x[1];
    if(u==p) continue;
    dfs(u,c,d+co);
    dp[c]=min(dp[c],dp[u]);
    maxi[c]=max(maxi[c],maxi[u]);
  }  

  if(maxi[c]<=ck+2*d-dp[c]) {
    maxi[c]=-INF; 
    return;
  }

  int u = maxi[c];
  
  if(u>ck+d){ 
  	ok=0;
  	return;
  }
  
  if(c==1){
  	vis[c]=1;
  	dp[c]=d;
  	maxi[c]=-INF;
  	return;
  }
  
  if(u-depth[p]>ck){
  	vis[c]=1;
  	dp[c]=d;
  	maxi[c]=-INF;
  	return;
  }
}

bool check(int x){

  ok=1;
  fill(dp,dp+N,INF);
  fill(vis,vis+N,0);
  fill(maxi,maxi+N,-INF);
  ck=x;

  dfs(1,0,0);

  if(ok && count(vis,vis+N,1)<=k) return 1;
  return 0;
}


void solve(){

  cin >> n >> k;
  for(int i=1;i<n;i++){
  	int a,b,c;
  	cin >> a >> b >> c;
  	v[a].pb({b,c});
  	v[b].pb({a,c});
  }

  int l=0,r=(int)1e15;
 
  while(l<r){
  	int m=(l+r)/2;
  	if(check(m)) r=m;
  	else l=m+1;
  }

  cout << l << endl;

  check(l);

  vector<int> ans;
  for(int i=1;i<=n;i++) if(vis[i]) ans.pb(i);
  for(int i=1;i<=n;i++) if(!vis[i] && sz(ans)<k) ans.pb(i);
  

  for(int x:ans) cout << x << " ";
  cout << endl;
}

int32_t main(){

  cin.tie(0); ios::sync_with_stdio(0);
  
  int t=1;//cin >> t;
  while(t--) solve();

  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 60 / 60