Compilare: user.cpp: In function ‘int main()’: user.cpp:78:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < ctc.size(); ++i) { ^ user.cpp:79:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < ctc[i].size(); ++j) { ^ user.cpp: In function ‘void read_input()’: user.cpp:27:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:30:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &y); ^ user.cpp: In function ‘int main()’: user.cpp:71:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.in", "r", stdin); ^ user.cpp:72:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ctc.out", "w", stdout); ^