Submission #1030845

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Source Code Expand

#define DEB
#include<bits/stdc++.h>
#define REP(i,m) for(int i=0;i<(m);++i)
#define REPN(i,m,in) for(int i=(in);i<(m);++i)
#define ALL(t) (t).begin(),(t).end()
#define CLR(a) memset((a),0,sizeof(a))
#define pb push_back
#define mp make_pair
#define fr first
#define sc second

using namespace std;


#ifdef DEB
#define dump(x)  cerr << #x << " = " << (x) << endl
#define prl cerr<<"called:"<< __LINE__<<endl
#define dumpR(x) cerr<<"\x1b[31m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
#define dumpY(x) cerr<<"\x1b[33m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
#define dumpG(x) cerr<<"\x1b[32m"<<#x<<" = " <<(x)<<"\x1b[39m"<<endl
template<class T> void debug(T a,T b){ for(;a!=b;++a) cerr<<*a<<' ';cerr<<endl;}
#else
#define dump(x) ;
#define dumpR(x) ;
#define dumpY(x) ;
#define dumpG(x) ;
#define prl ;
template<class T> void debug(T a,T b){ ;}
#endif

template<class T> void chmin(T& a,const T& b) { if(a>b) a=b; }
template<class T> void chmax(T& a,const T& b) { if(a<b) a=b; }

typedef long long int lint;
typedef pair<int,int> pi;

namespace std{
  template<class S,class T>
  ostream &operator <<(ostream& out,const pair<S,T>& a){
    out<<'('<<a.fr<<','<<a.sc<<')';
    return out;
  }
}

const double INF=1e10;

int n;
pi ps[20];
double d[20][20];
int ar[20];
double sq(double a){
  return a*a;
}
struct uf{

  static const int MAXN=18;
  int par[MAXN];
  int size[MAXN];
  void init(){
    memset(par,-1,sizeof(par));
    REP(i,MAXN) size[i]=1;
  }
  int root(int a){
    if(par[a]==-1) return a;
    return par[a]=root(par[a]);
  }
  void unite(int a,int b){
    a=root(a);b=root(b);
    if(a==b) return;
    if(size[a]<size[b]) swap(a,b);

    par[b]=a;
    size[a]+=size[b];
  }
  bool same(int a,int b){
    return root(a)==root(b);
  }
};


uf u;
vector<int> g[20];
pair<double,pi> es[150];

double dfs(int v,int p,double thr){
  double cur=ar[v];
  for(auto to:g[v]){
    if(to==p) continue;
    double a=dfs(to,v,thr);
    if(a>0){
      cur-=d[v][to]+a;
    }else{
      cur+=max(0.0,-a-d[v][to]);
    }
  }
  return -(cur-thr);
}
bool check(double thr,int r){
  double req=dfs(r,-1,thr);
  if(req<=0) return true;
  return false;
}
double calc(int bit){
  int m=0;
  int r=-1;
  REP(i,n) g[i].clear();
  REP(i,n) if(bit>>i&1){
    REP(j,i) if(bit>>j&1){
      es[m++]=mp(d[i][j],mp(i,j));
    }
    r=i;
  }
  sort(es,es+m);
  u.init();
  REP(i,m){
    int a=es[i].sc.fr,b=es[i].sc.sc;
    if(!u.same(a,b)){
      u.unite(a,b);
      g[a].pb(b);
      g[b].pb(a);
    }
  }

  double lb=0,ub=1e9+10;
  REP(i,100){
    double md=(lb+ub)/2;
    if(check(md,r)) lb=md;
    else ub=md;
  }
  return lb;
}

double wat[1<<15];
double dp[1<<15];
int main(){
  cin>>n;
  REP(i,n){
    cin>>ps[i].fr>>ps[i].sc>>ar[i];
  }
  REP(i,n) REP(j,n) {
    d[i][j]=sqrt(sq(ps[i].fr-ps[j].fr)+sq(ps[i].sc-ps[j].sc));
  }

  REP(i,1<<n) if(i>0){
    wat[i]=calc(i);
  }
  dp[0]=INF;
  for(int i=1;i<(1<<n);++i){
    int cur=i;
    do{
      chmax(dp[i],min(wat[cur],dp[i^cur]));
      cur=(cur-1)&i;
    }while(cur>0);
  }
  printf("%.10f\n",dp[(1<<n)-1]);
  return 0;
}

Submission Info

Judge Result