Compilare: user.cpp: In function ‘std::pair<long long int, long int> isKey(long long int)’: user.cpp:16:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<C[wh].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:48:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trapeze2.in","r",stdin); ^ user.cpp:49:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trapeze2.out","w",stdout); ^ user.cpp:51:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld %lld",&x1,&d1,&n1); x1 <<= 1; d1 <<= 1; ^ user.cpp:52:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld %lld %lld",&x2,&d2,&n2); x2 <<= 1; d2 <<= 1; ^