Cod sursa(job #2662345)

Utilizator divianegoescuDivia Negoescu divianegoescu Data 23 octombrie 2020 21:57:32
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.47 kb
#include <fstream>
#include <vector>
#define K 1002
#include <bitset>
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
int n,m,i,x,y,z,c[K][K],q[K],t[K],flux,scad,vecin;
bitset <K> viz;
vector <int> v[K];
int bfs(){ // verif daca mai exista lant care sa ajunga in nodul n
    int p,u;
    viz.reset();
    q[1]=viz[1]=1;
    for(p=u=1;p<=u;p++){
        int nod=q[p];
        for(int i=0;i<v[nod].size();i++){
            int vecin=v[nod][i];
            if(!viz[vecin] && c[nod][vecin]>0){
                q[++u]=vecin;
                viz[vecin]=1;
                t[vecin]=nod;
                if(vecin==n)
                    return 1;
            }
        }
    }
    return 0;
}
int main(){
    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>x>>y>>z;
        v[x].push_back(y);
        v[y].push_back(x);
        c[x][y]=z; //capacitate
        //c[y][x]=0 muchie fictiva inversata
    }
    while(bfs()){
        for(i=0;i<v[n].size();i++){
            vecin=v[n][i];
            if(viz[vecin] && c[vecin][n]>0){
                scad=c[vecin][n];
                for(x=vecin;t[x];x=t[x])
                    scad=min(scad,c[t[x]][x]);
                c[vecin][n]-=scad;
                c[n][vecin]+=scad;
                flux+=scad;
                for(x=vecin;t[x];x=t[x])
                    c[t[x]][x]-=scad,
                    c[x][t[x]]+=scad;
            }
        }
    }
    fout<<flux;
    return 0;
}