Cod sursa(job #1940067)

Utilizator MaligMamaliga cu smantana Malig Data 26 martie 2017 13:10:04
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.93 kb
#include <iostream>
#include <fstream>
#include <iomanip>
#include <cmath>
#include <algorithm>

using namespace std;
ifstream in("cmap.in");
ofstream out("cmap.out");

const int NMax = 1e5 + 5;
typedef long long ll;
const ll inf = 3e18;

int N;
struct elem {
    int x,y;
}v[NMax],aux[NMax];
bool operator <(elem a,elem b) {
    if (a.y == b.y) {
        return a.x < b.x;
    }
    return a.y < b.y;
}

ll dist(elem,elem);
ll solve(int,int);
bool cmp(elem,elem);

int main()
{
    in>>N;
    for (int i=1;i<=N;++i) {
        in>>v[i].x>>v[i].y;
    }
    sort(v+1,v+N+1,cmp);

    out<<fixed<<setprecision(6)<<sqrt(solve(1,N))<<'\n';
    in.close();out.close();
    return 0;
}

ll solve(int st,int dr) {
    if (st == dr) {
        return inf;
    }
    if (dr-st+1 == 2) {
        if (!(v[st] < v[dr])) {
            swap(v[st],v[dr]);
        }

        return dist(v[st],v[dr]);
    }

    int mij = (st+dr)>>1,
        abscisa = v[mij].x;
    ll mn = min(solve(st,mij),solve(mij+1,dr));

    int nrAux = 0,i = st, j = mij+1;
    while (i <= mij && j <= dr) {
        if (v[i] < v[j]) {
            aux[++nrAux] = v[i++];
        }
        else {
            aux[++nrAux] = v[j++];
        }
    }
    while (i <= mij) {
        aux[++nrAux] = v[i++];
    }
    while (j <= dr) {
        aux[++nrAux] = v[j++];
    }

    for (i=1;i<=nrAux;++i) {
        v[st+i-1] = aux[i];
    }

    nrAux = 0;
    double root = sqrt(mn);
    for (i=st;i<=dr;++i) {
        if (abs(v[i].x - abscisa) <= root) {
            aux[++nrAux] = v[i];
        }
    }

    for (i=1;i<=nrAux;++i) {
        for (int j=i+1;j<=nrAux && j-i+1 <= 8;++j) {
            mn = min(mn,dist(aux[i],aux[j]));
        }
    }

    return mn;
}

ll dist(elem a,elem b) {
    return 1LL * (a.x - b.x) * (a.x - b.x) + 1LL * (a.y - b.y) * (a.y - b.y);
}

bool cmp(elem a,elem b) {
    return a.x < b.x;
}