Compilare: main.cpp: In function 'int main()': main.cpp:30:25: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &n); ^ main.cpp:38:31: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%lld", &x); ^ main.cpp: In function 'void ciur()': main.cpp:17:16: warning: iteration 1000005 invokes undefined behavior [-Waggressive-loop-optimizations] if(!c[i]) ~~~^ main.cpp:15:19: note: within this loop for(int i=2; i<=N; ++i) ^