Submission #54091

#	Time	Username	Problem	Language	Result	Execution time	Memory
54091		Bodo171	Circle selection (APIO18_circle_selection)	C++14	0 / 100	2 ms	492 KiB

circle_selection

#include <iostream>
#include <fstream>
#include <algorithm>
#include <set>
using namespace std;
const int nmax=100005;
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 tt[nmax];
int n,i,j,ind;
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;
}
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;
    }
    return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:24:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("data.in","r",stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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