Compilare: user.cpp: In function ‘bool subsir(std::string, std::string)’: user.cpp:12:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<b.size();j++) ^ user.cpp:13:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i<a.size() and a[i]==b[j]) ++i; ^ user.cpp:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return i==a.size(); ^ user.cpp: In function ‘int main()’: user.cpp:54:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<sol.size();i++) ^