Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:53:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); ++ i) ^ user.cpp: In function ‘void dfs2(int)’: user.cpp:89:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); ++ i) { ^ user.cpp:94:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < graph[node].size() && found < 1; ++ j) ^ user.cpp:103:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (; j < graph[node].size() && found < 2; ++ j) ^ user.cpp:118:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); ++ i) ^ user.cpp:127:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < graph[node].size(); ++ i) { ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:16:47: 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); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:38:51: 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); ^