Compilare: main.cpp: In function 'void dfs(int, std::vector<int>)': main.cpp:22:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < fii[x].size(); i++) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void dfs2(int)': main.cpp:32:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < fii[x].size(); i++) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'void solve()': main.cpp:60:15: warning: 'root' may be used uninitialized in this function [-Wmaybe-uninitialized] dfs2(root); ^