Compilare: main.cpp: In function 'void sol()': main.cpp:25:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (u<v[c[l].second].size()) ~^~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:55:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("conexidad.in","r",stdin); ^ main.cpp:56:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen ("conexidad.out","w",stdout); ^ main.cpp:57:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &n, &m); ^ main.cpp:66:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d", &x, &y); ^