Compilare: main.cpp: In function 'int main()': main.cpp:46:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( j = 0 ; j < a[i].size() ; j++ ) fout << a[i][j] << ' '; ~~^~~~~~~~~~~~~ main.cpp: In function 'void bfs1(int)': main.cpp:58:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < v1[nod].size() ; i++ ) if ( viz1[v1[nod][i]] == 0 ) bfs1 ( v1[nod][i] ); ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'void bfs2(int)': main.cpp:67:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 0 ; i < v2[nod].size() ; i++ ) if ( viz2[v2[nod][i]] == 0 ) bfs2 ( v2[nod][i] ); ~~^~~~~~~~~~~~~~~~