Compilare: user.cpp: In function ‘int main(int, const char**)’: user.cpp:58:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < d.size(); ++i) ^ user.cpp:68:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < d.size(); ++i) ^ user.cpp:20:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("exp.in", "r", stdin); ^ user.cpp:21:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("exp.out", "w", stdout); ^ user.cpp:24:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &m, &n); ^ user.cpp:45:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^