Compilare: user.cpp: In function ‘void Solve()’: user.cpp:69:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=x[1]+1; i<=a; i++) ^ user.cpp: In function ‘void Back(int, long long int, int)’: user.cpp:80:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s == a) ^ user.cpp:81:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(p == b) ^ user.cpp:87:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<=fr[k]; i++) ^ user.cpp:89:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s + i <= a) ^