Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:103:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < list[node].size(); i++) { ^ user.cpp: In function ‘int main()’: user.cpp:139:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < queries.size(); i++) { ^ user.cpp:144:48: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < nodes[it].size(); j++) { ^ user.cpp:114:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("arb.out", "w", stdout); ^ user.cpp: In member function ‘void Buffer::reFill()’: user.cpp:45:43: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(&data[0], 1, dim, stdin); ^ user.cpp: In constructor ‘Buffer::Buffer(std::string, int)’: user.cpp:20:46: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(name.c_str(), "r", stdin); ^