Compilare: main.cpp: In function 'int main()': main.cpp:28:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=2; i<s1.length()-1; ++i) { ~^~~~~~~~~~~~~~ main.cpp:45:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (s1[i]!='0' && z[i] != m && i<=s1.length()-m-1 && i>m+1 && s1[i + z[i]]<s1[z[i] + 1]) ++sol; ~^~~~~~~~~~~~~~~~~