Cod sursa(job #2272535)

Utilizator stefan_creastaStefan Creasta stefan_creasta Data 30 octombrie 2018 11:47:26
Problema Flux maxim Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.4 kb

#include <queue>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <climits>
using namespace std;
const int NMAX = 1005;
vector <int> g[NMAX];
int cap[NMAX][NMAX];
bool viz[NMAX];
int deUnde[NMAX];
bool bfs(int nod, int n) {
  queue <int> q;
  q.push(nod);
  viz[nod] = 1;
  deUnde[nod] = nod;
  while(!q.empty() && !viz[n]) {
    int u = q.front();
    q.pop();
    for(auto v : g[u]) {
      if(!viz[v] && cap[u][v] > 0) {
        q.push(v);
        viz[v] = 1;
        deUnde[v] = u;
      }
    }
  }
  return viz[n];
}
void init(int n) {
  for(int i = 1; i <= n; i++) {
    viz[i] = 0;
  }
}


int main() {
  int n, m;
  freopen("maxflow.in", "r", stdin);
  freopen("maxflow.out", "w", stdout);
  scanf("%d%d", &n, &m);
  for(int i = 1; i <= m; i++) {
    int x, y, c;
    scanf("%d%d%d", &x, &y, &c);
    g[x].push_back(y);
    g[y].push_back(x);
    cap[x][y] = c;
  }
  int sol = 0;
  while(bfs(1, n)) {
    for(auto v : g[n]) {
      if(viz[v] && cap[v][n]) {
        int minim = INT_MAX;
        deUnde[n] = v;
        int poz = n;
        while (poz != 1) {
          minim = min(minim, cap[deUnde[poz]][poz]);
          poz = deUnde[poz];
        }
        poz = n;
        while (poz != 1) {
          cap[deUnde[poz]][poz] -= minim;
          cap[poz][deUnde[poz]] += minim;
          poz = deUnde[poz];
        }
        sol += minim;
      }
    }
    init(n);
  }
  printf("%d\n", sol);
  return 0;
}