Compilare: user.cpp: In function 'void build_graph()': user.cpp:29: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'void build(int)': user.cpp:62: warning: overflow in implicit constant conversion user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int bf()': user.cpp:88: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'bool posibil(int)': user.cpp:121: warning: unused variable 'i'