Edmonds-Karp (BFS) algo

#define II pair<int,int>
VI parent;
int res[MAXN][MAXN]; //adjMat for residual network
VII adjList;
//                                         MaxFlow   BFS
// Edmonds-Karp Algo,  BFS with adjList [ O(V.E/2   (V+E))  ~  O(V.E^2) ]
int bfs(int src, int dest){
  fill(all(parent), -1);
  parent[src]=-2;
  queue<II> q; q.push({src, INF});
  while(!q.empty()){
    int u = q.front().F;
    int f = q.front().S;
    q.pop();
    for(auto v:adjList[u]){
      if(parent[v]==-1 && res[u][v]>0){
        parent[v]=u;
        int nf = min(f, res[u][v]);
        if(v==dest) return nf;
        q.push({v, nf});
      }
    }
  }
  return 0;
}
int MaxFlow(int src, int dest){
  int max_flow=0;
  int inc_flow;
  while(inc_flow=bfs(src, dest)){
    max_flow += inc_flow;
    for(int u=dest ; u!=src ; u=parent[u]){
      res[parent[u]][u] -= inc_flow;
      res[u][parent[u]] += inc_flow;
    }
  }
  return max_flow;
}