/in/foo.cc: In function 'void Dijskra()':
/in/foo.cc:45:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < E[now].size(); ++i) {
                   ~~^~~~~~~~~~~~~~~
/in/foo.cc:40:24: warning: unused variable 'D' [-Wunused-variable]
   int now = Q.top().u, D = Q.top().dis;
                        ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:4:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i,a,n) for (int i=a;i<n;i++)
                                   
/in/foo.cc:75:7:
  rep (i, 0, Ans.size()) {
       ~~~~~~~~~~~~~~~~            
/in/foo.cc:75:2: note: in expansion of macro 'rep'
  rep (i, 0, Ans.size()) {
  ^~~