Cod sursa(job #1970441)

Utilizator MaligMamaliga cu smantana Malig Data 19 aprilie 2017 12:39:18
Problema Cele mai apropiate puncte din plan Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.92 kb
#include <iostream>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <iomanip>

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

#define pb push_back
typedef long long ll;
const int NMax = 1e5 + 5;
const ll inf = 9e18 + 5;

int N;

struct elem {
    ll x,y;
}v[NMax],aux[NMax];

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

ll solve(int,int);
ll dist(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);

    ll dist = solve(1,N);
    out<<fixed<<setprecision(6)<<sqrt(dist)<<'\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[dr] < v[st]) {
            swap(v[st],v[dr]);
        }
        return dist(v[st],v[dr]);
    }

    ll mij = (st+dr)>>1,
        abscisa = v[mij].x,
        mn = min(solve(st,mij),solve(mij+1,dr)),
        nrAux = 0;

    int 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=st;i<=dr;++i) {
        v[i] = aux[i - st + 1];
    }

    nrAux = 0;
    long 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 (j=i+1;j <= nrAux && j-i+1 <= 8;++j) {
            ll d = dist(aux[i],aux[j]);
            mn = min(mn,d);
        }
    }

    return mn;
}

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