Cod sursa(job #2453535)

Utilizator vlad082002Ciocoiu Vlad vlad082002 Data 4 septembrie 2019 12:46:16
Problema Flux maxim Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.44 kb
#include <fstream>
#include <vector>
#include <queue>
#include <iostream>
#define inf 100000000
using namespace std;

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

int capacitate[1024][1024], flux[1024][1024], t[1024], v[1024], n, m;
vector<int> g[1024];
queue<int> q;

int minim(int a, int b) {
    if(a < b)
        return a;
    return b;
}

int bfs() {
    for(int i = 1; i <= n; i++)
        v[i] = 0;
    int k;
    v[1] = 1;
    q.push(1);

    while(!q.empty()) {
        k = q.front();
        for(int i = 0; i < g[k].size(); i++) {
            int vecin = g[k][i];
            if(capacitate[k][vecin] != flux[k][vecin] && !v[vecin]) {
                v[vecin] = 1;
                q.push(vecin);
                t[vecin] = k;
            }
        }
        q.pop();
    }
    return v[n];
}

int main() {
    fin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int x, y, c;
        fin >> x >> y >> c;
        capacitate[x][y] += c;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    int flow, fmin;
    for(flow = 0; bfs(); flow += fmin) {
        fmin = inf;
        for(int nod = n; nod != 1; nod = t[nod]) {
            fmin = minim(fmin, capacitate[t[nod]][nod]-flux[t[nod]][nod]);
        }

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

    fout << flow;
}