foo.cc: In function 'int get(int, int)':
foo.cc:38:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < graph_r[node].size(); i++) {
                     ~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc: In function 'int work()':
foo.cc:85:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < graph[elem].size(); i++) {
                         ~~^~~~~~~~~~~~~~~~~~~~
foo.cc:56:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d%d", &n, &m, &k, &p);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:63:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d", &a, &b, &c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:105:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &T);
     ~~~~~^~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务