/in/foo.cc: In function 'void spfa()':
/in/foo.cc:23:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i=0; i<q.size(); i++) {
                ~^~~~~~~~~
/in/foo.cc: In function 'int f(int, int)':
/in/foo.cc:48:16: error: no match for 'operator[]' (operand types are 'std::pair<int, int>' and 'int')
    int u = edge[0], w = edge[1];
                ^
/in/foo.cc:49:23: error: 'w' was not declared in this scope
    ans = (ans + f(d - w, u)) % P;
                       ^