Compilare: main.cpp: In function 'void dfs(int)': main.cpp:16:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v[nod].size();i++){ ~^~~~~~~~~~~~~~ main.cpp:18:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=i+1;j<v[nod].size();j++){ ~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:32:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("petsoft.in","r",stdin); ^ main.cpp:33:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("petsoft.out","w",stdout); ^