Cod sursa(job #2592391)

Utilizator popashtefan10Popa Stefan popashtefan10 Data 1 aprilie 2020 17:32:18
Problema Flux maxim Scor 70
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.9 kb
#include <iostream>
#include <cstdio>
#include <vector>
#define NMAX 1000
#define MMAX 5000
#define INF 550000000

using namespace std;

struct muchie {
  int nod1, nod2, flux, cap;

  muchie(int nnod1 = 0, int nnod2 = 0, int fflux = 0, int ccap = 0) {
    nod1 = nnod1, nod2 = nnod2, flux = fflux, cap = ccap;
  }
};

bool uz[2 * MMAX + 5];
int n, m, flux_tot, flux;
int inv[2 * MMAX + 5], from[NMAX + 5];
muchie muchii[2 * MMAX + 5];
vector<int> v[NMAX + 5];

void dfs(int nod, int cf) {
  uz[nod] = true;
  if(nod == n) {
    flux = cf;
    return;
  }
  for(int x: v[nod]) {
    if(muchii[x].cap - muchii[x].flux == 0 || uz[muchii[x].nod2])
      continue;
    dfs(muchii[x].nod2, min(cf, muchii[x].cap - muchii[x].flux));
    if(flux) {
      muchii[x].flux += flux;
      muchii[inv[x]].flux -= flux;
      return;
    }
  }
}

int main() {
  freopen("maxflow.in", "r", stdin);
  freopen("maxflow.out", "w", stdout);
  int a, b, c;

  scanf("%d %d", &n, &m);
  for(int i = 1; i <= m; i++) {
    scanf("%d %d %d", &a, &b, &c);
    muchii[i] = muchie(a, b, 0, c);
    v[a].push_back(i);
  }

  for(int i = 1; i <= m; i++)
    if(!inv[i]) {
      for(int j = i + 1; j <= m; j++)
        if(!inv[j] && muchii[i].nod1 == muchii[j].nod2 && muchii[i].nod2 == muchii[j].nod1) {
          inv[i] = j;
          inv[j] = i;
          break;
        }
      if(!inv[i]) {
        muchii[++m] = muchie(muchii[i].nod2, muchii[i].nod1, 0, 0);
        inv[i] = m;
        inv[m] = i;
        v[muchii[i].nod2].push_back(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;
}