Cod sursa(job #2966412)

Utilizator IvanAndreiIvan Andrei IvanAndrei Data 17 ianuarie 2023 15:51:51
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.8 kb
#include <fstream>
#include <vector>
#include <queue>
#include <bitset>

using namespace std;

ifstream in ("maxflow.in");
ofstream out ("maxflow.out");

const int max_size = 1e3 + 1, INF = 1e9 + 1;

int cap[max_size][max_size], t[max_size], n;
vector <int> mc[max_size];
queue <int> q;
bitset <max_size> viz;

bool bfs ()
{
    queue <int> q;
    for (int i = 1; i <= n; i++)
    {
        viz[i] = 0;
        t[i] = 0;
    }
    viz[1] = 1;
    q.push(1);
    while (!q.empty())
    {
        int nod = q.front();
        q.pop();
        for (auto f : mc[nod])
        {
            if (!viz[f] && cap[nod][f] > 0)
            {
                t[f] = nod;
                viz[f] = 1;
                if (f == n)
                {
                    return true;
                }
                q.push(f);
            }
        }
    }
    return false;
}

int main ()
{
    int m;
    in >> n >> m;
    while (m--)
    {
        int x, y, z;
        in >> x >> y >> z;
        cap[x][y] += z;
        mc[x].push_back(y);
        mc[y].push_back(x);
    }
    int flux = 0;
    while (bfs())
    {
        for (auto f : mc[n])
        {
            if (cap[f][n] <= 0 || !viz[f])
                continue;
            t[n] = f;
            int mn = INF, nod = n;
            while (nod != 1)
            {
                mn = min(mn, cap[t[nod]][nod]);
                nod = t[nod];
            }
            if (mn == 0)
                continue;
            nod = n;
            while (nod != 1)
            {
                cap[t[nod]][nod] -= mn;
                cap[nod][t[nod]] += mn;
                nod = t[nod];
            }
            flux += mn;
        }
    }
    out << flux;
    in.close();
    out.close();
    return 0;
}