Cod sursa(job #2468795)

Utilizator maria15Maria Dinca maria15 Data 5 octombrie 2019 22:39:55
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.74 kb
#include <fstream>
#include <vector>
#include <deque>
#include <bitset>

using namespace std;

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

int n, m, i, j, t[1001], flux[1001][1001], cap[1001][1001], sol, a, b, c, tata, minim, nod;
deque<int> coada;
vector<int> v[1002];
bitset<1001> f;

bool bfs(){
    coada.push_back(1);
    f.reset();
    f[1] = 1;
    t[1] = 0;
    while(!coada.empty()){
        int p = coada[0];
        for(int i = 0;i<v[p].size();i++){
            int vecin = v[p][i];
            if(f[vecin] == 0 && cap[p][vecin] > flux[p][vecin]){
                f[vecin] = 1;
                t[vecin] = p;
                coada.push_back(vecin);
            }
        }
        coada.pop_front();
    }
    return f[n];
}

int main(){
    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>a>>b>>c;
        v[a].push_back(b);
        v[b].push_back(a);
        cap[a][b] = c;
    }
    while(bfs()){
        for(i=0;i<v[n].size();i++){
            b = v[n][i];
            if(f[b] == 1 && cap[b][n] > flux[b][n]){
                tata = b, nod = n, minim = cap[tata][nod] - flux[tata][nod];
                while(tata){
                    minim = min(minim, cap[tata][nod] - flux[tata][nod]);
                    nod = tata;
                    tata = t[nod];
                }
                tata = b, nod = n;
                if(minim != 0){
                    while(tata){
                        flux[tata][nod] += minim;
                        flux[nod][tata] -= minim;
                        nod = tata;
                        tata = t[nod];
                    }
                }
                sol += minim;
            }
        }
    }
    fout<<sol;
    return 0;
}