Compilare: main.cpp: In function 'int main()': main.cpp:38:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<G[who].size();++i) ~^~~~~~~~~~~~~~ main.cpp:16:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n, &m, &k); ^ main.cpp:19:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&c); ^