Compilare: user.cpp: In function ‘int main()’: user.cpp:6:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("exp.in","r",stdin); ^ user.cpp:7:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("exp.out","w",stdout); ^ user.cpp:9:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&m,&n); ^ user.cpp:12:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&nr); ^ user.cpp:46:15: warning: iteration 30004u invokes undefined behavior [-Waggressive-loop-optimizations] if(v[i]) ^ user.cpp:45:14: note: containing loop for(i=1;i<=30005;i++) ^