Compilare: main.cpp: In function 'void dfs(int)': main.cpp:33:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<v[na].size(); i++) ~^~~~~~~~~~~~~ main.cpp:39:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j<v[na].size(); j++) ~^~~~~~~~~~~~~ main.cpp:46:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (it = 0; it<d[i].size(); it++) ~~^~~~~~~~~~~~ main.cpp:61:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (k = 0; k<d[i].size(); k++) ~^~~~~~~~~~~~