Compilare: main.cpp: In function 'int main()': main.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[nod].size();j++) ~^~~~~~~~~~~~~~ main.cpp:26:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in","r",stdin); ^ main.cpp:27:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out","w",stdout); ^ main.cpp:33:9: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized] int x,y; ^