Compilare: user.cpp: In function ‘int main()’: user.cpp:44:17: warning: unused variable ‘x’ [-Wunused-variable] int n,m,i=0,x=0,y,a,b,c=1; ^ user.cpp:44:21: warning: unused variable ‘y’ [-Wunused-variable] int n,m,i=0,x=0,y,a,b,c=1; ^ user.cpp:45:10: warning: unused variable ‘s’ [-Wunused-variable] char s[2000001]; ^