Cod sursa(job #1167789)

Utilizator manciu_ionIon Manciu manciu_ion Data 5 aprilie 2014 22:22:54
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 kb
#include <cstdio>
#include <cstring>
#include <vector>

using namespace std;

#define NMAX 1024
#define pb push_back
#define sz size()
#define mp make_pair
#define INF 0x3f3f3f3f

int C[NMAX][NMAX];
int F[NMAX][NMAX];
int TT[NMAX];
vector<int> G[NMAX];
int N, M;
int cd[NMAX];
int viz[NMAX];

int BF()
{
    int i, j, nod, V;

    cd[0] = 1;
    cd[1] = 1;
    memset(viz, 0, sizeof(viz));
    viz[1] = 1;

    for (i = 1; i <= cd[0]; i++)
    {
        nod = cd[i];
        for (j = 0; j < G[nod].sz; j++)
            {
                V = G[nod][j];
                if (C[nod][V] == F[nod][V] || viz[V]) continue;
                viz[V] = 1;
                cd[ ++cd[0] ] = V;
                TT[V] = nod;
                if (V == N) return 1;
            }
    }

    return 0;
}

int main()
{
    freopen("maxflow.in", "rt", stdin);
    freopen("maxflow.out", "wt", stdout);

    int i, flow, fmin, x, y, z, nod;

    scanf("%d %d ", &N, &M);

    for (i = 1; i <= M; i++)
    {
        scanf("%d %d %d ", &x, &y, &z);
        C[x][y] += z;
        G[x].pb(y);
        G[y].pb(x);
    }

    for (flow = 0; BF(); flow += fmin)
    {
        fmin = INF;
        for (nod = N; nod != 1; nod = TT[nod])
            fmin = min(fmin, C[ TT[nod] ][nod] - F[ TT[nod] ][nod]);
        for (nod = N; nod != 1; nod = TT[nod])
        {
            F[ TT[nod] ][nod] += fmin;
            F[nod][ TT[nod] ] -= fmin;
        }
    }

    printf("%d\n", flow);

    fclose(stdin);
    fclose(stdout);
    return 0;
}