Compilare: user.cpp: In function ‘void dfs1(int)’: user.cpp:59:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < graph[node].size(); ++ i) { ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:81:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < graph[node].size(); ++ i) { ^ user.cpp:94:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < graph[node].size(); ++ i) ^ user.cpp:108:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); ++ i) ^ user.cpp:110:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < graph[node].size(); ++ i) { ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:39:39: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, 1, SIZE, in); ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:13:35: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, 1, SIZE, in); ^