Compilare: user.cpp: In function ‘void trans(int)’: user.cpp:24:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j+1>=k.size()) j--; ~~~^~~~~~~~~~ user.cpp:25:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] else if(j+2<k.size() && k[j]==k[j+1]) j++; ~~~^~~~~~~~~