Compilare: user.cpp: In function ‘int main()’: user.cpp:101:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < sol.size(); ++j) { ^ user.cpp:83:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("desen.in", "r", stdin); ^ user.cpp:84:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("desen.out", "w", stdout); ^ user.cpp:87:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:90:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^