Compilare: user.cpp: In function ‘void bfs1(int)’: user.cpp:47:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < a[x].size(); i++) ~~^~~~~~~~~~~~~ user.cpp: In function ‘void bfs2(int)’: user.cpp:64:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < a[x].size(); i++) ~~^~~~~~~~~~~~~ user.cpp: In function ‘void bfs1(int)’: user.cpp:55:7: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] last = x; ~~~~~^~~ user.cpp: In function ‘void bfs2(int)’: user.cpp:73:7: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] last = x; ~~~~~^~~