Compilare: user.cpp: In function ‘bool bf()’: user.cpp:31:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<L[x].size();i++) { ^ user.cpp:20:15: warning: unused variable ‘s’ [-Wunused-variable] int fr,sc,s; ^ user.cpp: In function ‘int main()’: user.cpp:71:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<L[l+r+1].size();i++) { ^ user.cpp:96:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<L[i].size()-1;j++) ^