Cod sursa(job #2462607)

Utilizator DanutAldeaDanut Aldea DanutAldea Data 27 septembrie 2019 17:33:38
Problema Cele mai apropiate puncte din plan Scor 75
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.69 kb
#include <fstream>
#include <cmath>
#include <algorithm>
#include <iomanip>
#define x first
#define y second
using namespace std;

ifstream fin("cmap.in");
ofstream fout("cmap.out");

long long n,i,j;
pair <long long,long long> v[100001],r[100001],w[100001];

long long dist(pair<long long,long long> a, pair<long long,long long> b){
    return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);
}

long long inter(long long st, long long mid, long long dr){
    long long i=st;
    long long j=mid+1;
    long long k=st-1;

    while(i<=mid && j<=dr){
        if(v[i].y<v[j].y)
            r[++k]=v[i++];
        else
            r[++k]=v[j++];
    }

    for(;i<=mid;i++)
        r[++k]=v[i];
    for(;j<=dr;j++)
        r[++k]=v[j];

    for(i=st;i<=dr;i++)
        v[i]=r[i];
}

long long solve(long long st, long long dr){
    long long sol,i,j,r,r1,r2;

    if(dr-st==1){
        r=dist(v[st],v[dr]);
        inter(st,st,dr);
        return r;
    }
    if(dr-st==2){
        r=min(dist(v[st],v[dr]),min(dist(v[st+1],v[st]),dist(v[st+1],v[dr])));
        inter(st,st,dr-1);
        inter(st,dr-1,dr);
        return r;
    }

    long long mid=(st+dr)/2;

    r1=solve(st,mid);
    r2=solve(mid+1,dr);
    sol=min(r1,r2);

    long long cnt=0;
    for(i=st;i<=dr;i++){
        if(abs(v[mid].x-v[i].x)<=sol){
            w[++cnt]=v[i];
        }
    }

    for(i=1;i<cnt;i++)
        for(j=i+1;j<=min(cnt,i+7);j++)
            sol=min(sol,dist(w[i],w[j]));

    return sol;
}

int main(){
    fin>>n;
    for(i=1;i<=n;i++)
        fin>>v[i].x>>v[i].y;
    sort(v+1,v+n+1);

    fout<<setprecision(7)<<fixed<<(double)sqrt(solve(1,n));

    return 0;
}