Cod sursa(job #2957082)

Utilizator mirceaspPetcu Mircea mirceasp Data 21 decembrie 2022 17:31:35
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.95 kb
#include <iostream>
#include <bits/stdc++.h>
#include <fstream>

#define mx 1001
using namespace std;
ifstream f("maxflow.in");
ofstream g("maxflow.out");
int n, m, x, y, capacitate;
int rgraf[mx][mx];

bool bfs(int s, int d, vector<int> &tata, vector<bool> &vizitat) {
    queue<int> q;
    vizitat[s] = true;
    tata[s] = -1;
    q.push(s);
    while (!q.empty()) {
        int front = q.front();
        q.pop();
        for (int i = 1; i < n + 1; ++i) {

            if (vizitat[i] == false && rgraf[front][i] > 0) {
                if (i == n) {
                    tata[i] = front;
                    return true;
                }
                vizitat[i] = true;
                q.push(i);
                tata[i] = front;
            }
        }
    }
    //daca se poate ajunge la destinatie
    return vizitat[n];
}

int main() {
    f >> n >> m;
    vector<int> tata(n + 1, -1);
    for (int i = 0; i < m; ++i) {


        f >> x >> y >> capacitate;
        rgraf[x][y] = capacitate;

    }

    int fluxTotal = 0;
    vector<bool> vizitat(n + 1, false);
    while (bfs(1, n, tata, vizitat)) {
        for (int i = 1; i <= n; i++) {
            if (vizitat[i] == true and rgraf[i][n] > 0) {
                //iau un nod ce are o muchie nesaturata cu nodul final
                tata[n] = i;
                int flux = INT_MAX;
                int u = n;
                while (u != 1) {
                    int x = rgraf[tata[u]][u];
                    flux = min(flux, x);
                    u = tata[u];
                }
                u = n;
                while (u != 1) {
                    int vecin = tata[u];
                    rgraf[vecin][u] -= flux;
                    rgraf[u][vecin] += flux;
                    u = tata[u];
                }
                fluxTotal += flux;

            }

        }
        tata.resize(n + 1, -1);
        for (int j = 1; j <= n; ++j) {
            vizitat[j] = false;
        }
    }
    g << fluxTotal;
    return 0;
}