Compilare: user.cpp: In function ‘void df(int)’: user.cpp:18:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < fiu[n].size(); i++) ^ user.cpp:24:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < fiu[n].size(); i++) ^ user.cpp:44:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < fiu[n].size(); i++) ^ user.cpp:45:41: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if (!viz[fiu[n][i]] & tmin[fiu[n][i]] == tmax) ^ user.cpp: In function ‘int main()’: user.cpp:83:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < mut[t].size(); i++) ^ user.cpp:101:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < mut[i].size(); j++) ^ user.cpp:54:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("optic.in", "r", stdin); ^ user.cpp:56:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:60:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &i, &j); ^ user.cpp:92:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("optic.out", "w", stdout); ^