Compilare: user.cpp: In function ‘void prefix()’: user.cpp:16:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < a.size(); ++i) { ^ user.cpp: In function ‘void kmp()’: user.cpp:29:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < b.size(); ++i) { ^ user.cpp:34:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(k == a.size() - 1) { ^ user.cpp: In function ‘int main()’: user.cpp:51:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < apps.size(); ++i) ^