Submission #332189

#	Time	Username	Problem	Language	Result	Execution time	Memory
332189		DanerZein	Odašiljači (COCI20_odasiljaci)	C++14	70 / 70	154 ms	8804 KiB

odasiljaci

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef pair<double,ii> iii;
const ll MAX=1e9;
int ns;
double raiz(ll x){
  double l=0,r=MAX;
  for(int i=0;i<=40;i++){
    double mid=(l+r)/2;
    if(mid*mid>=x)r=mid;
    else l=mid;
  }
  return r;
}
int pa[1010];
void init(int n){
  for(int i=0;i<n;i++) pa[i]=i;
  ns=n;
}
int findset(int i){
  if(pa[i]==i) return pa[i];
  return pa[i]=findset(pa[i]);
}
bool issameset(int i,int j){
  return findset(i)==findset(j);
}
void unionset(int i,int j){
  if(!issameset(i,j)){
    int x=findset(i),y=findset(j);
    ns--;
    pa[x]=y;;
  }
}
vector<ii> x;
bool check(double r,int n){
  init(n);
  //cout<<r<<endl;
  for(int i=0;i<n-1;i++){
    for(int j=i+1;j<n;j++){
      if(!issameset(i,j)){
	double a=abs(x[i].first-x[j].first);
	double b=abs(x[i].second-x[j].second);
	double dist=raiz((a*a)+(b*b));
	dist/=2;
	//	cout<<i<<" "<<j<<" "<<dist<<" "<<r<<" "<<ns<<endl;
	if(dist<=r) unionset(i,j);
      }
    }
  }
  if(ns==1) return true;
  return false;
}
int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin>>n;
  for(int i=0;i<n;i++){
    int a,b;
    cin>>a>>b;
    x.push_back(ii(a,b));
  }
  priority_queue<iii,vector<iii>,greater<iii> > pq;
  for(int i=0;i<n-1;i++){
    for(int j=i+1;j<n;j++){
      double a=abs(x[i].first-x[j].first);
      double b=abs(x[i].second-x[j].second);
      double dist=sqrt((a*a)+(b*b));
      dist/=2;
      pq.push(iii(dist,ii(i,j)));
    }
  }
  double mi=-1;
  init(n);
  while(!pq.empty()){
    int u,v;
    double dist;
    u=pq.top().second.first;
    v=pq.top().second.second;
    dist=pq.top().first;
    pq.pop();
    if(!issameset(u,v)){
      mi=max(mi,dist);
    }
    unionset(u,v);
  }printf("%.7f\n",mi);
}

• Subtask 1: 70 / 70