Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:20:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0 ; i < v[nod].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:79:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j <= ans.size()/2; j++) ^ user.cpp:82:56: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = ans.size()/2 + 1; j < ans.size(); j++) ^ user.cpp:91:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < rt[i].size(); j++) ^