Spoj topological sort

:point_right: https://www.spoj.com/problems/RPLA/

Khan’s algo :
using simple queue and sorting

while(!mq.empty()){
           int  v = mq.front();
           mq.pop();
           if(SZ(G[v]) == 0) continue;
           for(int u : G[v]){
               id[u]--;
               if(id[u] == 0){
                   mq.push(u);
                   vp.pb(mp(u, r)); // push_back and make pair
               }
           }
           ++r;
       }

Issue with the code is : node at same lvl are ranked with different numbers.

example

2 0
1 0
3 1
4 2
node 3 and 4 on same lvl but ranked diff.

i have tried priority queue, but ended with worse.