Cod sursa(job #2961420)

Utilizator 4N70N1U5Antonio Nitoi 4N70N1U5 Data 6 ianuarie 2023 14:48:38
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.54 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

int cap[1001][1001], flow[1001][1001], n, m, max_flow, current_flow;
vector<int> vis, pred;
vector<vector<int>> adj;

bool bfs()
{
    fill(vis.begin(), vis.end(), 0);
    fill(pred.begin(), pred.end(), 0);

    vis[1] = 1;
    pred[1] = 1;

    queue<int> q;
    q.push(1);

    while (!q.empty())
    {
        int c = q.front();

        q.pop();

        if (c == n)
            return true;

        for (int i = 0; i < adj[c].size(); i++)
        {
            if (!vis[adj[c][i]] && flow[c][adj[c][i]] < cap[c][adj[c][i]])
            {
                q.push(adj[c][i]);
                pred[adj[c][i]] = c;
                vis[adj[c][i]] = 1;
            }
        }
    }
    
    return false;
}

int main()
{
    fin >> n >> m;

    vis.resize(n + 1);
    pred.resize(n + 1);
    adj.resize(n + 1);

    for (int i = 0; i < m; i++)
    {
        int x, y, z;
        fin >> x >> y >> z;

        adj[x].push_back(y);
        adj[y].push_back(x);

        cap[x][y] = z;
    }

    while (bfs())
    {
        current_flow = __INT_MAX__;

        for (int i = n; i != 1; i = pred[i])
        {
            current_flow = min(current_flow, cap[pred[i]][i] - flow[pred[i]][i]);
        }

        for (int i = n; i != 1; i = pred[i])
        {
            flow[pred[i]][i] += current_flow;
            flow[i][pred[i]] -= current_flow;
        }

        max_flow += current_flow;
    }

    fout << max_flow;

    return 0;
}