Cod sursa(job #1937701)

Utilizator FragentisMihai Petru Fragentis Data 24 martie 2017 10:05:49
Problema Flux maxim Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.95 kb
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

typedef int Integer;
constexpr Integer INTEGER_MAX = 0x7fffffff;

vector<Integer> g[1001];
unsigned n, m;

Integer* capacity[1001];
Integer* flux[1001];
int p[1001];
bool viz[1001];

void getAugmentationPath(unsigned v)
{
    viz[v] = true;

    for(auto u : g[v])
    {
        if(viz[u] == true)
            continue;
        if(capacity[v][u] - flux[v][u] <= 0)
            continue;

        getAugmentationPath(u);

        if(p[n] != -1 || u == n)
        {
            p[u] = v;
            return;
        }
    }
}

Integer FordFulkerson()
{
    Integer flux_max = 0;

    while(true)
    {
        fill(viz + 1, viz + n + 1, false);
        fill(p + 1, p + n + 1, -1);

        getAugmentationPath(1);
        if(p[n] == -1)
            break;

        Integer flux_min = INTEGER_MAX;
        for(unsigned v = n; p[v] != -1; v = p[v])
            flux_min = min(flux_min, capacity[p[v]][v] - flux[p[v]][v]);
        flux_max += flux_min;

        for(unsigned v = n; p[v] != -1; v = p[v])
        {
            flux[p[v]][v] += flux_min;
            flux[v][p[v]] -= flux_min;
        }
    }

    return flux_max;
}

int main()
{
    cin >> n >> m;
    for(unsigned i = 1; i <= n; ++i)
    {
        capacity[i] = new Integer[n + 1];
        flux[i] = new Integer[n + 1];

        fill(capacity[i] + 1, capacity[i] + n + 1, 0);
        fill(flux[i] + 1, flux[i] + n + 1, 0);
    }

    for(unsigned i = 0; i < m; ++i)
    {
        unsigned x, y;
        Integer cap;
        cin >> x >> y >> cap;
        g[x].push_back(y);
        capacity[x][y] = cap;
        capacity[y][x] = -cap;
    }

    fill(p, p + n + 1, -1);

    Integer flux_max = FordFulkerson();

    for(unsigned i = 1; i <=n; ++i)
    {
        delete[] capacity[i];
        delete[] flux[i];
    }

    cout << flux_max;

    return 0;
}