Compilare: main.cpp: In function 'int main()': main.cpp:27:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 2; i < a.size(); ++i) { ~~^~~~~~~~~~ main.cpp:29:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i + z[i] < a.size() && a[i+z[i]] == a[1 + z[i]]) ++ z[i]; ~~~~~~~~~^~~~~~~~~~ main.cpp:34:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i + z[i] < a.size() && a[i + z[i]] == a[1 + z[i]]) ++ z[i]; ~~~~~~~~~^~~~~~~~~~