Compilare: user.cpp: In function ‘int get_comun(int, int)’: user.cpp:10:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < L[x].size(); i ++ ) ^ user.cpp:11:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < L[y].size(); j ++ ) ^ user.cpp: In function ‘int get_necomun(int)’: user.cpp:18:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < L[x].size(); i ++ ) ^ user.cpp: In function ‘int main()’: user.cpp:26:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "puzzle2.in" , "r", stdin ); ^ user.cpp:27:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "puzzle2.out", "w", stdout ); ^ user.cpp:29:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d", &N, &M ); ^ user.cpp:31:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d", &X, &Y ); ^