Compilare: user.cpp: In function ‘int main()’: user.cpp:63:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < set_two.size(); ++i) ^ user.cpp:77:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < set_one.size(); ++j) { ^ user.cpp:84:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < set_one.size(); ++i) ^ user.cpp:41:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alianta.in", "r", stdin); ^ user.cpp:42:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("alianta.out", "w", stdout); ^ user.cpp:45:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &tests); ^ user.cpp:48:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:51:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &xx, &yy); ^