Submission #54107

#	Time	Username	Problem	Language	Result	Execution time	Memory
54107		Bodo171	Circle selection (APIO18_circle_selection)	C++14	19 / 100	1318 ms	41612 KiB

circle_selection

#include <iostream>
#include <fstream>
#include <algorithm>
#include <set>
using namespace std;
const int nmax=300005;
pair<int,int>  v[nmax];
set< pair<int,int> > s;
set< pair<int,int> >::iterator it1,it2;
long long x[nmax],y[nmax],r[nmax];
int vv[nmax],pp[nmax];
int tt[nmax];
int n,i,j,ind;
struct event
{
    int val,wh,tip;
}ev[3*nmax];
bool ok(int A,int B)
{
    return (1LL*(x[A]-x[B])*(x[A]-x[B])+1LL*(y[A]-y[B])*(y[A]-y[B])<=1LL*(r[A]+r[B])*(r[A]+r[B]));
}
bool comp(pair<int,int> unu,pair<int,int> doi)
{
    if(unu.first==doi.first) return unu.second<doi.second;
    return unu.first>doi.first;
}
bool Cev(event unu,event doi)
{
    if(unu.val==doi.val) return unu.tip<doi.tip;
    return unu.val<doi.val;
}
int main()
{
    //freopen("data.in","r",stdin);
    cin>>n;
    bool zr=1;
    for(i=1;i<=n;i++)
    {
        cin>>x[i]>>y[i]>>r[i];
        v[i].first=r[i];
        v[i].second=i;
        if(y[i]!=0)
        {
            zr=0;
        }
    }
    if(n<=5000)
    {
        sort(v+1,v+n+1,comp);
        for(i=1;i<=n;i++)
            if(!tt[v[i].second])
        {
            tt[v[i].second]=v[i].second;
            for(j=i+1;j<=n;j++)
            {
                if(ok(v[i].second,v[j].second)&&(!tt[v[j].second]))
                    tt[v[j].second]=v[i].second;
            }
        }
        for(i=1;i<=n;i++)
            cout<<tt[i]<<' ';
        return 0;
    }
    if(zr)
    {
        int cap1,cap2;
        sort(v+1,v+n+1,comp);
        for(i=1;i<=n;i++)
        {
            cap1=x[i]-r[i];cap2=x[i]+r[i];
            s.insert({cap1,i});
            s.insert({cap2,i});
        }
        bool ok;
        for(i=1;i<=n;i++)
            if(!tt[v[i].second])
        {
            ind=v[i].second;tt[ind]=ind;
            cap1=x[ind]-r[ind];
            it1=s.lower_bound({cap1,0});ok=1;
            while((!s.empty())&&ok&&it1!=s.end())
            {
                it2=it1;it2++;
                if((*it1).first<=x[ind]+r[ind]&&(!tt[(*it1).second]))
                {
                    tt[(*it1).second]=ind;
                }
                s.erase(it1);
                if(it2==s.end()||((*it2).first>x[ind]+r[ind]))
                    ok=0;
                it1=it2;
            }
        }
        for(i=1;i<=n;i++)
            cout<<tt[i]<<' ';
        return 0;
    }
    int X,nr=0;
    for(i=1;i<=n;i++)
    {
        X=x[i];
        ev[++nr]={x[i]-r[i],i,1};
        ev[++nr]={x[i]+r[i]+1,i,-1};
    }
    sort(ev+1,ev+nr+1,Cev);
    for(i=1;i<=n;i++)
        vv[i]=y[i];
    for(i=1;i<=nr;i++)
    {
        if(ev[i].tip==-1)
        {
            s.erase({vv[ev[i].wh],ev[i].wh});
        }
        if(ev[i].tip==1)
        {
            if(!s.empty())
            {
                it1=s.lower_bound({vv[ev[i].wh],0});
                if(it1!=s.end())
                {
                    ind=(*it1).second;
                    if(ok(ev[i].wh,ind)) pp[ev[i].wh]=ind,pp[ind]=ev[i].wh;
                }
                if(it1!=s.begin())
                {
                    it1--;
                    ind=(*it1).second;
                    if(ok(ev[i].wh,ind)) pp[ev[i].wh]=ind,pp[ind]=ev[i].wh;
                }
            }
            s.insert({vv[ev[i].wh],ev[i].wh});
        }
    }
    for(i=1;i<=n;i++)
        if(r[pp[i]]>r[i]||(r[pp[i]]==r[i]&&pp[i]<i)) cout<<pp[i]<<' ';
        else cout<<i<<' ';
    return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:102:23: warning: narrowing conversion of '(x[i] - r[i])' from 'long long int' to 'int' inside { } [-Wnarrowing]
         ev[++nr]={x[i]-r[i],i,1};
                   ~~~~^~~~~
circle_selection.cpp:103:28: warning: narrowing conversion of '((x[i] + r[i]) + 1)' from 'long long int' to 'int' inside { } [-Wnarrowing]
         ev[++nr]={x[i]+r[i]+1,i,-1};
                   ~~~~~~~~~^~
circle_selection.cpp:98:9: warning: variable 'X' set but not used [-Wunused-but-set-variable]
     int X,nr=0;
         ^

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13