Compilare: user.cpp: In function ‘void solve()’: user.cpp:78:9: warning: unused variable ‘a’ [-Wunused-variable] int a=bfs(bfs(1).second).second; ^ user.cpp: In function ‘std::pair<int, int> bfs(int)’: user.cpp:51:16: warning: ‘k’ may be used uninitialized in this function [-Wmaybe-uninitialized] ww.second=k; ^