Compilare: user.cpp: In function ‘int main()’: user.cpp:57:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i<Sol.size(); ++i) { ^ user.cpp:21:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zeul.in", "r", stdin); ^ user.cpp:22:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &N, &M); ^ user.cpp:29:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &x, &y); ^