Compilare: user.cpp: In function ‘void iterativedfs()’: user.cpp:106:17: warning: unused variable ‘sz’ [-Wunused-variable] int sz=vf; ^ user.cpp:107:21: warning: unused variable ‘mid’ [-Wunused-variable] int l,r,mid,sol=q[1]; ^ user.cpp: In function ‘int main()’: user.cpp:152:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harbingers.in","r",stdin); ^ user.cpp:153:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("harbingers.out","w",stdout); ^ user.cpp:155:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:159:33: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&u,&w,&d); ^ user.cpp:164:48: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld%lld",&prepare[i],&speed[i]); ^