Compilare: main.cpp: In function 'char* verifica()': main.cpp:18:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0 ; j < graf[i].size() ; j++){ ~~^~~~~~~~~~~~~~~~ main.cpp:20:28: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] return "NU\n"; ^~~~~~ main.cpp:26:24: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] return "NU\n"; ^~~~~~ main.cpp:30:12: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings] return "DA\n"; ^~~~~~