Cod sursa(job #2955886)

Utilizator valentin12Valentin Ion Semen valentin12 Data 18 decembrie 2022 01:17:42
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.62 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>

using namespace std;

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

vector<vector<int>> v(1001);

int n, m, x, y, z, fluxMax;
int c[5005][5005], F[5005][5005], tata[1001], viz[1001], cc[5001];

int BFS()
{

    cc[0] = cc[1] = 1;
    memset(viz, 0, sizeof(viz));
    viz[1] = 1;

    for (int i = 1; i <= cc[0]; i++)
    {
        int nod = cc[i];
        if (nod == n)
            continue;
        for (int j = 0; j < v[nod].size(); j++)
        {
            int vecin = v[nod][j];
            if (c[nod][vecin] == F[nod][vecin] || viz[vecin])
                continue;

            viz[vecin] = 1;
            cc[++cc[0]] = vecin;
            tata[vecin] = nod;
        }
    }

    return viz[n];
}

int main()
{

    f >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        f >> x >> y >> z;
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y] = z;
    }

    while (BFS())
    {
        for (int i = 0; i < v[n].size(); i++)
        {
            int vecin = v[n][i];
            if (c[vecin][n] == F[vecin][n] || !viz[vecin])
                continue;

            int flux = 1 << 30;
            for (int nod = n; nod != 1; nod = tata[nod])
                flux = min(flux, c[tata[nod]][nod] - F[tata[nod]][nod]);

            for (int nod = n; nod != 1; nod = tata[nod])
            {
                F[tata[nod]][nod] += flux;
                F[nod][tata[nod]] -= flux;
            }

            fluxMax += flux;
        }
    }

    g << fluxMax;

    return 0;
}