Compilare: main.cpp: In function 'void cb(std::vector<int>&)': main.cpp:55:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i + gap < v.size(); ++i) { ~~~~~~~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:74:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(FIN, "r", stdin); ^ main.cpp:76:31: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(FOUT, "w", stdout); ^ main.cpp: In member function 'void IO::load()': main.cpp:37:37: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, L, stdin); ^