Compilare: main.cpp: In function 'int main()': main.cpp:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < x.size(); i++) ~~^~~~~~~~~~ main.cpp:34:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0, j = 0; i <= s.size() - n; i++){ ~~^~~~~~~~~~~~~~~ main.cpp:35:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < s.size() && j < i + n){ ~~^~~~~~~~~~