/in/foo.cc: In function 'void bfs(int)':
/in/foo.cc:19:25: error: return-statement with a value, in function returning 'void' [-fpermissive]
   if(t==e) return dist[t];
                         ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:36:40: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'll* {aka long long int*}' [-Wformat=]
  for(int i=1;i<=n;i++) scanf("%d",&a[i]);
                                        ^
/in/foo.cc:37:13: error: void value not ignored as it ought to be
  int k=bfs(s);
             ^
/in/foo.cc:37:6: warning: unused variable 'k' [-Wunused-variable]
  int k=bfs(s);
      ^