Cod sursa(job #2585678)

Utilizator RedXtreme45Catalin RedXtreme45 Data 19 martie 2020 12:11:52
Problema Flux maxim Scor 60
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.21 kb
#include <fstream>
#include <vector>
#include <queue>
#include <cstring>
#define INF 0x3f3f3f3f
#define Nmax 1001
using namespace std;
ifstream fin("maxflow.in");
ofstream fout("maxflow.out");
int n,m,f[Nmax][Nmax],c[Nmax][Nmax],min1,flux,ap[Nmax],venire[Nmax];
vector <int> G[Nmax];
int BFS(){
    memset(ap,0,sizeof ap);
    queue <int> q;
    q.push(1);
    ap[1]=1;
    while (!q.empty())
    {
        int x=q.front();
        q.pop();
        for (auto i:G[x])
        {
            if (c[x][i]==f[x][i] || ap[i]) continue;
            ap[i]=1;
            q.push(i);
            venire[i]=x;
            if (i==n)
                return 1;
        }
    }
    return 0;
}
int main()
{
    int i,a,b,y;
    fin>>n>>m;
    for (i=1;i<=m;i++)
    {
        fin>>a>>b>>y;
        G[a].push_back(b);
        c[a][b]+=y;
    }
    while (BFS())
    {
        min1=INF;
        i=n;
        while (i!=1)
        {
            min1=min(min1,c[venire[i]][i]-f[venire[i]][i]);
            i=venire[i];
        }
        i=n;
        while (i!=1)
        {
            f[venire[i]][i]+=min1;
            i=venire[i];
        }
        flux+=min1;
    }
    fout<<flux;
    return 0;
}