Compilare: user.cpp: In function ‘int main()’: user.cpp:29:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<c.size();) ^ user.cpp:31:5: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(n>0) if(s.at(n-1).at(m)+1==s.at(n).at(m)) ^ user.cpp:38:5: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if(m>0) if(s.at(n).at(m-1)+1==s.at(n).at(m)) ^