Compilare: main.cpp: In function 'void solve()': main.cpp:45:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<q[i].size();++j) ~^~~~~~~~~~~~ main.cpp:51:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0;k<v[nod].size();++k) ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:87:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tollroads.in","r",stdin); ^ main.cpp:89:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tollroads.out","w",stdout); ^ main.cpp:91:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&qr); ^ main.cpp:97:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&a,&b,&c); ^ main.cpp:109:44: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&usu[i].nod,&usu[i].t); ^