Compilare: user.cpp: In function ‘int main()’: user.cpp:16:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<s.size();i++) ^ user.cpp:18:58: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!x.empty() && x.top()<s[i] && x.size()+n-i>m)x.pop(); ^ user.cpp:13:15: warning: unused variable ‘j’ [-Wunused-variable] int n,m,i,j; ^