Compilare: user.cpp: In function ‘int build1(int)’: user.cpp:51:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < f[nod].size(); ++i) { ^ user.cpp:56:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int build2(int)’: user.cpp:61:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < f[nod].size(); ++i) { ^ user.cpp:73:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < f[nod].size(); ++i) { ^ user.cpp:90:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:12:47: 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:34:51: 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); ^