Compilare: main.cpp: In function 'int main()': main.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<(it->second).size();j++) ~^~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void fast()': main.cpp:21:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("cerc3.in","r",stdin); ^ main.cpp:22:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("cerc3.out","w",stdout); ^