Compilare: main.cpp: In function 'void Prim(int)': main.cpp:58:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod].size();i++) ~^~~~~~~~~~~~~~ main.cpp: In function 'int min_key()': main.cpp:43:12: warning: 'ind' may be used uninitialized in this function [-Wmaybe-uninitialized] return ind; ^~~ main.cpp: In function 'void Prim(int)': main.cpp:57:16: warning: 'ind' may be used uninitialized in this function [-Wmaybe-uninitialized] fr[nod]=true; ~~~~~~~^~~~~