Compilare: user.cpp: In function ‘void df(int, int)’: user.cpp:14:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[x].size() ; ++i) ^ user.cpp: In function ‘void run(int, int, int, int)’: user.cpp:29:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < g[x].size() ; ++i) ^ user.cpp: In function ‘int main()’: user.cpp:45:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.in" , "r" , stdin); ^ user.cpp:46:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arbxyz.out" , "w" , stdout); ^ user.cpp:48:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d" , &T) ; T ; --T) ^ user.cpp:50:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &n); ^ user.cpp:51:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &c[0]); ^ user.cpp:52:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &c[1]); ^ user.cpp:53:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &c[2]); ^ user.cpp:60:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &a); ^ user.cpp:61:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d" , &b); ^