foo.cc: In member function 'void dijkstra::dij(int, int, int)':
foo.cc:45:44: warning: narrowing conversion of '((dijkstra*)this)->dijkstra::dis[s]' from 'long long int' to 'int' inside { } [-Wnarrowing]
         dis[s] = 0; q.push((node) {s, dis[s]});
                                       ~~~~~^
foo.cc:55:68: warning: narrowing conversion of '((dijkstra*)this)->dijkstra::dis[v]' from 'long long int' to 'int' inside { } [-Wnarrowing]
                     dis[v] = dis[u] + w[i], q.push((node) {v, dis[v]});
                                                               ~~~~~^
foo.cc: In function 'int main()':
foo.cc:105:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("trans.in", "r", stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:106:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("trans.out", "w", stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc: In member function 'void dijkstra::solve()':
foo.cc:74:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%lld%d", &t, &n, &k, &m);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:77:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d%d%d", &x, &y, &z);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc:80:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &d);
         ~~~~~^~~~~~~~~~
foo.cc:83:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d%d%d", &u, &l, &r);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。