Compilare: main.cpp: In function 'void solve()': main.cpp:37:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<primes.size(); ++j){ ~^~~~~~~~~~~~~~ main.cpp: In function 'void bkt(ll, ll, ll, bool, bool)': main.cpp:79:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(last==divone[i].size()-1) return; ~~~~^~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void read()': main.cpp:27:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pairs.in", "r", stdin); ^ main.cpp:28:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &n); ^ main.cpp:29:47: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] for(i=1; i<=n; ++i) scanf("%lld", &val[i]); ^ main.cpp: In function 'void write()': main.cpp:61:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("pairs.out", "w", stdout); ^