Cod sursa(job #1937153)

Utilizator sebi110Ciobanu Sebastian sebi110 Data 23 martie 2017 19:13:31
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.39 kb
#include <fstream>
#include <vector>
#include <queue>
#include <string.h>
#define INF 2000000000
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
int c[1001][1001],f[1001][1001],p[1001];
bool viz[1001];
vector <int> vec[1001];
void getAP(int x)
{
    queue <int> q;
    q.push(x);
    viz[x]=1;
    while(!q.empty())
    {
        x=q.front();q.pop();
        int vecin;
        for(int i=0;i<vec[x].size();i++)
        {
            vecin=vec[x][i];
            if(viz[vecin]==0 && c[x][vecin]-f[x][vecin]>0)
            {
                p[vecin]=x;
                q.push(vecin);
                viz[vecin]=1;
            }
        }
    }
}
int main()
{
    int n,m,x,y,flux,i,maxf;
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y>>flux;
        vec[x].push_back(y);
        vec[y].push_back(x);
        c[x][y]=flux;
    }
    int F=0;
    while(1)
    {
        memset(viz,0,sizeof(viz));
        memset(p,-1,sizeof(p));
        getAP(1);
        if(p[n]==-1)
            break;
        maxf=INF;
        i=n;
        while(i!=1)
        {
            maxf=min(maxf,c[p[i]][i]-f[p[i]][i]);
            i=p[i];
        }
        i=n;
        while(i!=1)
        {
            f[p[i]][i]+=maxf;
            f[i][p[i]]-=maxf;
            i=p[i];
        }
        F=F+maxf;
    }
    fout<<F;
    return 0;
}