Compilare: main.cpp: In function 'int main()': main.cpp:17:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < strlen(s); ++j) ~~^~~~~~~~~~~ main.cpp:29:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (last[i].size() == L + 1) last[i].pop_back(); ~~~~~~~~~~~~~~~^~~~~~~~ main.cpp:34:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (last[i].size() == L + 1) { ~~~~~~~~~~~~~~~^~~~~~~~ main.cpp:44:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (last[i].size() == L + 1) ++ans; ~~~~~~~~~~~~~~~^~~~~~~~