Compilare: main.cpp: In function 'void dfs(int)': main.cpp:25:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g2[el].size(); ++i) ~~^~~~~~~~~~~~~~~ main.cpp:27:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[el].size(); ++i) ~~^~~~~~~~~~~~~~ main.cpp: In function 'void dfs2(int)': main.cpp:33:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g[el].size(); ++i) ~~^~~~~~~~~~~~~~ main.cpp:35:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < g2[el].size(); ++i) dfs2(g2[el][i]); ~~^~~~~~~~~~~~~~~