Cod sursa(job #2592386)

Utilizator popashtefan10Popa Stefan popashtefan10 Data 1 aprilie 2020 17:24:06
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.69 kb
#include <iostream>
#include <cstdio>
#include <vector>
#define NMAX 1000
#define MMAX 5000
#define INF 550000000

using namespace std;

struct muchie {
  int nod, flux, cap, ind;

  muchie(int nnod = 0, int fflux = 0, int ccap = 0, int iind = 0) {
    nod = nnod, flux = fflux, cap = ccap, ind = iind;
  }
};

bool uz[NMAX + 5];
int n, m, flux_tot, flux;
vector<muchie> v[NMAX + 5];

void dfs(int nod, int cf) {
  uz[nod] = true;
  if(nod == n) {
    flux = cf;
    return;
  }
  for(muchie &vec: v[nod]) {
    if(vec.cap - vec.flux == 0 || uz[vec.nod])
      continue;
    dfs(vec.nod, min(cf, vec.cap - vec.flux));
    if(flux) {
      vec.flux += flux;
      for(muchie &rvec: v[vec.nod])
        if(rvec.nod == nod) {
          rvec.flux -= flux;
          break;
        }
      return;
    }
  }
}

int main() {
  freopen("maxflow.in", "r", stdin);
  freopen("maxflow.out", "w", stdout);
  int x, y, z;

  scanf("%d %d", &n, &m);
  for(int i = 1; i <= m; i++) {
    scanf("%d %d %d", &x, &y, &z);
    v[x].push_back(muchie(y, 0, z, i));
  }

  for(int i = 2; i < n; i++)
    for(muchie vec: v[i]) {
      bool gasit = false;
      for(muchie rvec: v[vec.nod])
        if(rvec.nod == i) {
          gasit = true;
          break;
        }
      if(!gasit)
        v[vec.nod].push_back(muchie(i, 0, 0, ++m));
    }

  flux = 1;
  while(flux) {
    flux = 0;
    for(int i = 1; i <= n; i++)
      uz[i] = false;
    dfs(1, INF + 5);
    flux_tot += flux;
  }

//  for(int i = 1; i <= n; i++)
//    for(muchie vec: v[i])
//      printf("muchia (%d, %d) are flux %d/%d\n", i, vec.nod, vec.flux, vec.cap);

  printf("%d", flux_tot);

  return 0;
}