Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:53:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x].size();++i) ^ user.cpp: In function ‘int main()’: user.cpp:72:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<R[x].size();++j) ^ user.cpp:78:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(S[x].size()<k&&!H.empty()) ^ user.cpp:83:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(++L[K.B]<S[K.B].size()) ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:40:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:11:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^