Cod sursa(job #2532518)

Utilizator AndreiD31Dragan Andrei AndreiD31 Data 27 ianuarie 2020 21:59:02
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.65 kb
#include <bits/stdc++.h>

using namespace std;

ifstream f("maxflow.in");
ofstream g("maxflow.out");

int n,ok,t,maxflow,sol[1010],tata[1010],flux[1010][1010],c[1010][1010],viz[1010];
queue <int> q;
vector <int> v[1010];

void BFS()
{
    int i,nod,vecin;
    for(i=1;i<=n;i++)viz[i]=0;
    t=0;

    viz[1]=1;
    q.push(1);

    while(!q.empty())
    {
        nod=q.front();
        for(i=0;i<v[nod].size();i++)
        {
            vecin=v[nod][i];
            if(viz[vecin]==0 && flux[nod][vecin]<c[nod][vecin])
            {
                viz[vecin]=1;
                if(vecin==n)
                {
                    t++;
                    sol[t]=vecin;
                }
                tata[vecin]=nod;
                q.push(vecin);
            }
        }
        q.pop();
    }

    if(viz[n]==0){ok=0;return;}
    else ok=1;

    /// dam update la matricea flux
    for(i=1;i<=t;i++)
    {
        int flux_min=INT_MAX;
        nod=sol[i];
        while(tata[nod]!=0)
        {
            flux_min=min(flux_min,c[tata[nod]][nod]-flux[tata[nod]][nod]);
            nod=tata[nod];
        }
        maxflow+=flux_min;

        nod=sol[i];
        while(tata[nod]!=0)
        {
            flux[tata[nod]][nod]+=flux_min;
            flux[nod][tata[nod]]-=flux_min;
            nod=tata[nod];
        }
    }
}

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

    ok=1;
    while(ok)
    {
        ok=0;
        BFS();
    }

    g<<maxflow;
    return 0;
}