Compilare: main.cpp: In function 'void dfs(int)': main.cpp:67:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G[x].size();++j){ ~^~~~~~~~~~~~ main.cpp: In function 'void dfs2(int, int)': main.cpp:83:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<G[x].size();++j){ ~^~~~~~~~~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:19:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^