Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:18:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (o=0;o<l[i][z].size();o++) { ^ user.cpp:20:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (u=0;u<l[j][z].size();j++) { ^ user.cpp: In function ‘int main()’: user.cpp:31:15: warning: unused variable ‘o’ [-Wunused-variable] int i,j,t,o; ^