Compilare: main.cpp: In function 'int bfs()': main.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[u].size();i++) ~^~~~~~~~~~~~ main.cpp:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[n].size();i++) ~^~~~~~~~~~~~ main.cpp:37:18: warning: statement has no effect [-Wunused-value] for(u; t[u]; u=t[u]) ^ main.cpp:40:18: warning: statement has no effect [-Wunused-value] for(u; t[u]; u=t[u]) ^ main.cpp:47:1: warning: control reaches end of non-void function [-Wreturn-type] } ^