Cod sursa(job #2931643)

Utilizator toma_ariciuAriciu Toma toma_ariciu Data 31 octombrie 2022 17:51:12
Problema Adapost Scor 35
Compilator cpp-64 Status done
Runda Arhiva de probleme Marime 4.58 kb
/// Preset de infoarena
#include <fstream>
#include <cmath>
#include <iomanip>
#include <vector>
#include <queue>

using namespace std;

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

const double eps = 1e-6, inf = 1000000;
const int maxN = 805;
int n, m, sursa, dest;
double fake_dist[maxN], real_dist[maxN], dist[maxN], total_cost;
int prv[maxN], max_flow;
bool used[maxN];
struct muchie {
    int nxt, flux, cap;
    double cost;
}lm[165005];
vector <int> G[maxN];
struct haha4heap {
    int nod;
    double cost;
    bool operator < (const haha4heap &other) const {
        return cost > other.cost;
    }
};
priority_queue <haha4heap> heap;
queue <int> q;
struct point {
    double x, y;
}v1[405], v2[405];

double get_dist(int a, int b)
{
    double deltax = v1[a].x - v2[b].x, deltay = v1[a].y - v2[b].y;
    double d = sqrt(deltax * deltax + deltay * deltay);
    return d;
}

void bellman_ford()
{
    for(int i = sursa; i <= dest; i++)
        dist[i] = inf;
    dist[sursa] = 0;
    q.push(sursa);
    while(!q.empty())
    {
        int curr = q.front();
        q.pop();
        for(int ind : G[curr])
        {
            muchie aux = lm[ind];
            if(aux.cap == 0 || dist[curr] + aux.cost >= dist[aux.nxt])
                continue;
            dist[aux.nxt] = dist[curr] + aux.cost;
            q.push(aux.nxt);
        }
    }
}

bool dijkstra()
{
    for(int i = sursa; i <= dest; i++)
    {
        fake_dist[i] = inf;
        real_dist[i] = dist[i];
        used[i] = 0;
    }
    while(!heap.empty())
        heap.pop();
    fake_dist[sursa] = 0;
    dist[sursa] = 0;
    heap.push({sursa, 0});
    while(!heap.empty())
    {
        int curr = heap.top().nod;
        heap.pop();
        if(used[curr])
            continue;
        used[curr] = 1;
        for(int ind : G[curr])
        {
            muchie aux = lm[ind];
            if(aux.flux < aux.cap && fake_dist[curr] + aux.cost + real_dist[curr] - real_dist[aux.nxt] < fake_dist[aux.nxt])
            {
                prv[aux.nxt] = ind;
                fake_dist[aux.nxt] = fake_dist[curr] + aux.cost + real_dist[curr] - real_dist[aux.nxt];
                dist[aux.nxt] = dist[curr] + aux.cost;
                heap.push({aux.nxt, fake_dist[aux.nxt]});
            }
        }
    }
    if(fake_dist[dest] == inf)
        return 0;
    return 1;
}

void compute_flux(double val)
{
    for(int i = 0; i < n * n + 2 * n; i++)
    {
        lm[2 * i].flux = 0;
        lm[2 * i + 1].flux = 0;
        if(i < n * n)
        {
            if(lm[2 * i].cost <= val)
                lm[2 * i].cap = 1;
            else
                lm[2 * i].cap = 0;
        }
    }
    max_flow = 0;
    total_cost = 0;
    bellman_ford();
    while(dijkstra())
    {
        int min_flow = inf;
        for(int x = dest; x != sursa; x = lm[prv[x] ^ 1].nxt)
            min_flow = min(min_flow, lm[prv[x]].cap - lm[prv[x]].flux);
        for(int x = dest; x != sursa; x = lm[prv[x] ^ 1].nxt)
        {
            lm[prv[x]].flux += min_flow;
            lm[prv[x] ^ 1].flux -= min_flow;
        }
        total_cost +=1.0 *  min_flow * dist[dest];
        max_flow += min_flow;
    }
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n; i++)
        fin >> v1[i].x >> v1[i].y;
    for(int i = 1; i <= n; i++)
        fin >> v2[i].x >> v2[i].y;
    sursa = 0;
    dest = 2 * n + 1;
    int k = 0;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= n; j++)
        {
            double cst = get_dist(i, j);
            lm[2 * k] = {n + j, 0, 1, cst};
            lm[2 * k + 1] = {i, 0, 0, -cst};
            G[i].push_back(2 * k);
            G[n + j].push_back(2 * k + 1);
            k++;
        }
    }
    for(int i = 1; i <= n; i++)
    {
        lm[2 * k] = {i, 0, 1, 0};
        lm[2 * k + 1] = {sursa, 0, 0, 0};
        G[sursa].push_back(2 * k);
        G[i].push_back(2 * k + 1);
        k++;
    }
    for(int i = 1; i <= n; i++)
    {
        lm[2 * k] = {dest, 0, 1, 0};
        lm[2 * k + 1] = {n + i, 0, 0, 0};
        G[n + i].push_back(2 * k);
        G[dest].push_back(2 * k + 1);
        k++;
    }
    double st = 0, dr = 1500, ans = 1500;
    while(st + eps <= dr)
    {
        double med = (st + dr) / 2;
        compute_flux(med);
        if(max_flow == n)
        {
            ans = med;
            dr = med;
        }
        else
            st = med;
    }
    compute_flux(ans);
    fout << setprecision(6) << fixed << ans << ' ' << total_cost << '\n';
    return 0;
}