Compilare: user.cpp: In function ‘int main()’: user.cpp:16:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < s.size(); ++i) { ~~^~~~~~~~~~ user.cpp:23:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 2; i < m.size() - 1; ++i) { ~~^~~~~~~~~~~~~~ user.cpp:28:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (pi[i] <= i && pi[i] + i < m.size() && m[pi[i] + i] == m[i - pi[i]]) { ~~~~~~~~~~^~~~~~~~~~