Compilare: main.cpp: In function 'void precompute()': main.cpp:14:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < str.size(); ++i) ~~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:49:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < str.size(); ++i) { ~~^~~~~~~~~~~~ main.cpp:31:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("laundering.in","r",stdin); ^ main.cpp:32:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("laundering.out","w",stdout); ^