Compilare: main.cpp: In function 'void bfs(int)': main.cpp:18:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<G[x].size();++i){ ~^~~~~~~~~~~~ In file included from /usr/include/string.h:635:0, from /usr/include/c++/6/cstring:42, from main.cpp:4: In function 'void* memset(void*, int, size_t)', inlined from 'void bfs(int)' at main.cpp:13:24: /usr/include/x86_64-linux-gnu/bits/string3.h:90:70: warning: call to void* __builtin___memset_chk(void*, int, long unsigned int, long unsigned int) will always overflow destination buffer return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest)); ^