Compilare: user.cpp: In function ‘void bkt(std::string, int, int, int)’: user.cpp:23:9: warning: suggest parentheses around comparison in operand of ‘&’ [-Wparentheses] if(a==0&b==0&&l==m&&s.size()==n) { ^ user.cpp:23:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(a==0&b==0&&l==m&&s.size()==n) { ^ user.cpp:27:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()==n) ^