Compilare: user.cpp: In function ‘void makeOG(int, int)’: user.cpp:17:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[act].size() ; ++i) ^ user.cpp: In function ‘void dfs(int, int)’: user.cpp:37:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < og[act].size() ; ++i) ^ user.cpp:47:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < order.size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:75:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortop.in" , "r" , stdin); ^ user.cpp:76:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortop.out" , "w" , stdout); ^ user.cpp:78:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ user.cpp:79:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &k); ^ user.cpp:83:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &a); ^ user.cpp:84:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &b); ^ user.cpp:95:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &fix[i].second); ^ user.cpp:96:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &fix[i].first); ^