Compilare: user.cpp: In member function ‘bool PalTree::finished()’: user.cpp:22:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return last >= s.length(); ^ user.cpp: In function ‘int main()’: user.cpp:64:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pscpld.in", "r", stdin); ^ user.cpp:65:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pscpld.out", "w", stdout); ^