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Cod sursa(job #978086)

Utilizator crisbodnarCristian Bodnar crisbodnar Data 27 iulie 2013 19:55:41
Problema Adapost Scor 27
Compilator cpp Status done
Runda Arhiva de probleme Marime 2.42 kb
#include <iostream>
#include <fstream>
#include <queue>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <iomanip>

#define ff first
#define ss second
#define newn a[x][i]

using namespace std;

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

const int N = 410;
const int M = 820;
const int s = 0, d = 815;
const int oo = 0x3f3f3f3f;

typedef pair <double, double> nod;
vector <nod> sold;
vector <int> a[M];
vector <bool> uz(M);
int n, f[M][M], c[M][M], t[M];
double cst[M][M], dist[M], cmin;
queue <int> q;

void Read()
{
    fin>>n;
    for(int i=1; i<=n; i++)
    {
        double x, y;
        fin>>x>>y;
        c[s][i] = 1;
        a[s].push_back(i);
        sold.push_back(nod(x, y));
    }
    for(int i=1; i<=n; i++)
    {
        double x, y; int vf = i + n;
        fin>>x>>y;
        c[vf][d] = 1;
        a[vf].push_back(d);
        for(int j=0; j<n; j++)
        {
            c[j+1][vf] = 1;
            a[j+1].push_back(vf);
            a[vf].push_back(j+1);
            double difx = x - sold[j].ff, dify = y - sold[j].ss;
            double cost = sqrt(difx*difx + dify*dify);
            cst[j+1][vf] = cost;
            cst[vf][j+1] = -cost;
        }
    }
}

inline bool Bellman_Ford(const double val)
{
    for(int i=1; i<=2*n+1; i++) dist[i] = oo;
    dist[d] = oo;
    uz.assign(n*2+1, 0);
    q.push(s); uz[s] = 1; dist[s] = 0;
    while(!q.empty())
    {
        int x = q.front(); q.pop(); uz[x] = 0;
        for(unsigned i=0; i<a[x].size(); i++)
             if(f[x][newn] < c[x][newn] && val >= cst[x][newn])
                if(dist[x] + cst[x][newn] < dist[newn])
                {
                    t[newn] = x;
                    dist[newn] = dist[x] + cst[x][newn];
                    if(!uz[newn]) uz[newn] = 1, q.push(newn);
                }
    }
    return (dist[d] != oo);
}

inline bool OK(const double val)
{
    int flux = 0; cmin = 0;
    memset(f, 0, sizeof f);
    while(Bellman_Ford(val))
    {
        for(int j=d; j!=s; j=t[j])
            f[t[j]][j]++, f[j][t[j]]--;
        flux++;
        cmin += dist[d];
    }
    return (flux == n);
}

int main()
{
    Read();
    double st = 0, dr = 2000, mid;
    while(dr - st > 0.0001)
    {
        mid = (dr+st) / 2;
        if(OK(mid)) dr = mid;
        else st = mid;
    }
    fout<<fixed<<setprecision(5)<<dr<<' '<<cmin;
    return 0;
}